Cedar Rapids, Iowa (CNN) Maggie Willems loves Joe Biden , but with each passing month, she also likes Elizabeth Warren more and more.

"It would be fair to say that Biden is my head and Warren is my heart," said Willems, reflecting on the Democratic presidential race at a Labor Day picnic here. "I do love Joe, but Biden would be my pragmatic choice and Warren would be a little leap of faith in my heart."

Five months before the Iowa caucuses open the 2020 Democratic nominating contest , the decision weighing on Willems is one that rests at the heart of the party's quest to win the White House. Democrats are united around the goal of defeating President Donald Trump, yet utterly uncertain of who can get the job done.

The Democratic primary campaign, which remained remarkably stable throughout the summer, is suddenly entering a new period of uncertainty. Many voters say they are just beginning to pay close attention to the race, signaling the potential for a far more volatile campaign season this fall.

Interviews with voters, campaign advisers and party strategists make at least one point clear: The race is likely far more fluid than most polls suggest, with decisions rooted in far more than ideology, and the question of electability looming over it all. Warning lights may be blinking for some leading candidates, and opportunities could still exist for other contenders struggling to break through.

"To be fair, I have not ruled almost anyone out," said Willems, a high school social studies teacher and volleyball coach in Mount Vernon, Iowa. "Everyone told us Donald Trump wasn't electable, which obviously wasn't true, so I'm really struggling with the narrative that so-and-so might not be electable."

Electability -- and its many definitions -- is one of the key prisms in which the next chapter of the race is viewed, but it's also an incredibly subjective one, with little consensus among voters on whether a pragmatic or a progressive path is the best.

The dynamic between Biden and Warren is coming into sharper focus, as they prepare to share a debate stage next week for the first time. More than a dozen other rivals are also building up campaign organizations, winning over supporters and making their cases to voters.

Bernie Sanders is the only other candidate who routinely garners double-digit support in polls and remains in the top tier of contenders, with Kamala Harris, Pete Buttigieg and others fighting to break into that group.

As the campaign turns a corner, a rising sense of urgency is hanging in the air for several candidates. These questions are among those that will frame the discussion for the next chapter of the Democratic primary fight:

Can Biden hold his lead?

Biden not only survived the summer, he also put to rest any question of whether the first day of his campaign would be his best one.

While he's leading in nearly every poll, he hasn't taken command of the race or settled an even bigger concern among Democrats: Is he really the strongest candidate to defeat Trump?

That premise, which lies at the core of his candidacy, faces a new test this fall as rivals increasingly try to persuade Democrats that he would be a risky nominee. It's a delicate balance, given the affection many Democrats feel for Biden.

"I love Joe Biden," said Lydia Wermager, a retiree from nearby Marion, who saw the former vice president at the Labor Day picnic here. "But I think we need somebody with a bigger vision and that's why I'm looking at the younger candidates."

Her vest was decorated with campaign buttons from years gone by, including Barack Obama, Bill Clinton and Al Gore. Her current choice in 2020? Pete Buttigieg.

With an Iowa victory far from certain, Biden advisers say they are preparing for a lengthy Democratic primary battle, drawing on a deep reservoir of support among African Americans, particularly older voters. So far, at least, all of Biden's rivals have struggled to erode his support among black voters.

So for all of the importance of starting off with a strong performance in Iowa, it's the South Carolina firewall that Biden's campaign is relying on to sustain him through what his advisers concede could be a challenging few months ahead.

Can anyone survive September's exclusion?

Ten Democratic candidates -- the same number that will be on the debate stage next week in Houston -- are about to see whether anyone can survive being on the outside looking in on the third Democratic debate.

The prospect of missing the debate already contributed to the departures of Washington Gov. Jay Inslee, Rep. Seth Moulton of Massachusetts and Sen. Kirsten Gillibrand of New York, all of whom factored the lack of media attention into their decisions to drop out.

But a number of candidates are pressing forward, arguing that the debates won't matter and they can survive the exclusion.

"My overall plan is it doesn't end until the early states have voted," Montana Gov. Steve Bullock told CNN. "So I'm going continue to do exactly what I have been doing. Hopefully I'll be on the October stage."

He added: "These DNC rules, they might have been well-intentioned, but when you lose all the governors in this race other than me, it's showing that something's not quite working here. The debate rules don't actually decide who's going be your nominee or who will be the next president."

For candidates like billionaire Tom Steyer and Rep. Tulsi Gabbard of Hawaii, both of whom got close to qualifying for the third debate, the decision to stay in and hope to qualify for the October debate is easy.

But it's an open question how long the candidates can go by missing the chance to make their cases to millions of voters in the television audience.

Voters are ready for some to say goodbye

Matt Spellman, a 49-year-old Democrat from Cedar Rapids, didn't mince words when asked about the candidates who aren't going to make the September debate.

"It's too big," Spellman said. "It really is. I'm ready (for people to drop out). It's getting to be too overwhelming."

His thoughts were echoed by Lee Clancey, a former mayor of Cedar Rapids.

"We are getting to a point where we need to start winnowing the field," Clancey said. "I would like to see people who have not broken out of the pack take a back seat."

A number of Democratic candidates are holding out hope that they, despite the odds, can rise from off the debate stage and win the party's presidential nomination.

But is that best for the party? Voters certainly don't think so and would like to see some of the least successful candidates end their campaigns.

There are plenty of upcoming pressure points that could force candidates to bow out.

It's hard enough to explain to donors why you didn't make the third debate in Houston, but it is infinitely harder to do the same if you miss the fourth in October.

The viability of candidates who missed the third debate will also be most apparent in October, when campaigns must release their fundraising numbers to the Federal Election Commission.

For many of these campaigns, financial viability could be the most real pressure point. A key example: After spending millions on TV and digital ads in the closing weeks of her campaign, Gillibrand ended her campaign -- sources said -- with $800,000 in the bank, a paltry number considering she entered the race with a more than $10 million war chest.

Booker and O'Rourke need breakouts

Sen. Cory Booker of New Jersey and former Rep. Beto O'Rourke of Texas entered the 2020 race with high expectations.

Neither has lived up to the hype so far.

But both candidates qualified for the September debate and will look to use the prime-time stage -- with all the front-runners together -- to make their marks and break out.

Whether Booker and O'Rourke are able to create a moment is one hurdle, however. The second is whether they can seize the resulting momentum.

That is what Sen. Kamala Harris of California failed to do after the first debate in June. Harris scored what is now clearly seen as the high point of her campaign when she excoriated Biden for his past questionable positions on race, leading her to quickly jump in the polls.

But she has been unable to capitalize on that and has been on a steady decline since she landed a solid punch against the race's front-runner.

Harris aides are unmoved that their candidate was unable to build on the first debate. The campaign has plowed millions into organizing, has spent money to stay on TV in Iowa and has begun to build an operation in California, which will have a Super Tuesday presidential primary in 2020 -- taking such an early and coveted spot for the first time since 2008 -- and where the senator has leveraged her local status to consistently poll among the top candidates in the state.

Is Warren more like Obama or Dean?

Presidential campaigns often have breakout stars of the summer whose candidacies are tested anew in the fall. Playing that role in the 2020 race is Sen. Elizabeth Warren of Massachusetts.

She's built one of the most robust campaign organizations in Iowa. She's proved that she can raise money from grassroots supporters, without relying on a network of high-dollar donors. And she's often driving the policy discussion.

Many of those plans, which helped her campaign flourish, will soon face tougher scrutiny. She survived the first two debates largely unscathed, unapologetically offering her pitch for revolutionary change in Washington.

She is gaining a considerable following, but she also faces the challenge of persuading skeptical Democrats that her plans are not only possible, but also affordable.

"She's trafficking in a kind of utopianism that we don't really need right now," said Joe Gorton, a professor at the University of Northern Iowa. "We need really good, pragmatic, responsible leaders who evaluate the world as it is."

Democrats in Iowa have a long history of falling for liberal candidates at this stage in the race before turning to more moderate alternatives before the year ends. It's an open question whether this campaign season is any different.

Yet comparisons to Howard Dean, the former Vermont governor who captivated the party's liberal base 16 years ago this summer, are slowly fading. In Iowa and New Hampshire, Warren's operation is far more comparable to Obama's than Dean's, whose campaign largely collapsed before the Iowa caucuses in 2004.

Warren still faces questions of electability, including at a Labor Day stop in New Hampshire, when a voter told her that people "love her policies, but can she really beat Donald Trump?"

"What's going to carry us as Democrats is not playing it safe," Warren replied, adding that "I know how to fight and I know how to win."

Photos: Former presidential candidate Elizabeth Warren Photos: Former presidential candidate Elizabeth Warren Elizabeth Warren, a US senator from Massachusetts, speaks during a campaign event in March 2019. Hide Caption 1 of 45 Photos: Former presidential candidate Elizabeth Warren Warren is held by her father, Donald Herring, soon after she was born in Oklahoma City in 1949. "My daddy worked hard his whole life," Warren said when she posted this picture to Facebook on Father's Day 2014. "He sold fencing and carpeting, and ended up as a maintenance man. He and my mother never had much, but he said that his life was a success because his four kids had more opportunities than he had." Hide Caption 2 of 45 Photos: Former presidential candidate Elizabeth Warren A young Warren sits with her mother, Pauline. "When I was 12, my daddy had a heart attack," Warren wrote on Facebook in 2017. "All three of my brothers were off in the military, and Daddy was out of work for a long time. We lost our family station wagon, and we were about an inch away from losing our home. One day, I walked into my mother's room and found her crying. She said, 'We are not going to lose this house.' She wiped her eyes, blew her nose, and pulled on her best dress -- the one she wore to funerals and graduations. At 50 years old, she walked down the street and got her first paying job: answering the phones at Sears. That minimum wage job saved our home, and my mother saved our family." Hide Caption 3 of 45 Photos: Former presidential candidate Elizabeth Warren Warren poses for a Christmas photo with her brother John. All three of her brothers served in the military. Hide Caption 4 of 45 Photos: Former presidential candidate Elizabeth Warren In the late 1960s, Warren attended George Washington University on a debate scholarship. She dropped out after two years to get married, but she graduated from the University of Houston in 1970. Hide Caption 5 of 45 Photos: Former presidential candidate Elizabeth Warren Warren holds her newborn daughter, Amelia, in 1971. She and her first husband, Jim Warren, had two children before divorcing in 1980. Hide Caption 6 of 45 Photos: Former presidential candidate Elizabeth Warren Warren with her three brothers -- Don, John and David -- in 1980. After graduating from college, Warren worked as a speech pathologist at a New Jersey elementary school. She then got a law degree and taught at the Rutgers School of Law before becoming a professor at the University of Houston Law Center. She's also been a professor at the University of Texas Law School, the University of Pennsylvania Law School and Harvard Law School. Hide Caption 7 of 45 Photos: Former presidential candidate Elizabeth Warren Warren and her second husband, Bruce Mann. She posted this old photo to Facebook in 2016 along with a story about how she proposed to him. They were married in 1980. Hide Caption 8 of 45 Photos: Former presidential candidate Elizabeth Warren Warren teaches at the University of Pennsylvania Law School in the early 1990s. Hide Caption 9 of 45 Photos: Former presidential candidate Elizabeth Warren US Sen. Barack Obama listens to Warren speak during a roundtable discussion about predatory lending in 2008. Warren is an expert on bankruptcy law and was an adviser to the National Bankruptcy Review Commission in the 1990s. In 1989, Warren co-authored the book "As We Forgive Our Debtors: Bankruptcy and Consumer Credit in America." Hide Caption 10 of 45 Photos: Former presidential candidate Elizabeth Warren Warren takes her seat to testify before the House Budget Committee in 2009. The United States was battling a recession at the time, and Warren had been appointed to a congressional oversight panel overseeing the $700 billion Troubled Assets Relief Program. Hide Caption 11 of 45 Photos: Former presidential candidate Elizabeth Warren Warren and Treasury Secretary Timothy Geithner listen to President Barack Obama at the White House in September 2010. Obama was appointing Warren to be his assistant and special adviser to the Treasury Secretary in order to launch the Consumer Financial Protection Bureau. Warren had long called for a federal agency designed to protect consumers from fraudulent or misleading financial products. Hide Caption 12 of 45 Photos: Former presidential candidate Elizabeth Warren Warren and US Sen. Scott Brown, right, make fun of each other during an annual St. Patrick's Day breakfast in Boston. Warren announced in 2011 that she would be challenging Brown for his Senate seat.. Hide Caption 13 of 45 Photos: Former presidential candidate Elizabeth Warren Warren speaks to constituents at a campaign event in Scituate, Massachusetts, in May 2012. Hide Caption 14 of 45 Photos: Former presidential candidate Elizabeth Warren Warren takes a morning walk with her dog Otis on the Harvard University Business School campus in May 2012. Hide Caption 15 of 45 Photos: Former presidential candidate Elizabeth Warren Warren stands with family members after giving a speech in Springfield, Massachusetts, in June 2012. Warren has several grandchildren. Hide Caption 16 of 45 Photos: Former presidential candidate Elizabeth Warren President Barack Obama greets Warren at a fundraiser in Boston in June 2012. Hide Caption 17 of 45 Photos: Former presidential candidate Elizabeth Warren Warren speaks at the Democratic National Convention in September 2012. Hide Caption 18 of 45 Photos: Former presidential candidate Elizabeth Warren Warren greets supporters during a campaign event at Boston University. Hide Caption 19 of 45 Photos: Former presidential candidate Elizabeth Warren Warren takes the stage after defeating Brown for a Senate seat in November 2012. Hide Caption 20 of 45 Photos: Former presidential candidate Elizabeth Warren Warren listens during a hearing of the Senate Committee on Banking, Housing and Urban Affairs in May 2013. Hide Caption 21 of 45 Photos: Former presidential candidate Elizabeth Warren Warren meets with Supreme Court nominee Merrick Garland in April 2016. Hide Caption 22 of 45 Photos: Former presidential candidate Elizabeth Warren Warren campaigns with Democratic presidential candidate Hillary Clinton in June 2016. Hide Caption 23 of 45 Photos: Former presidential candidate Elizabeth Warren Warren, a member of the Senate Banking Committee, questions Wells Fargo CEO John Stumpf in September 2016. Warren unleashed a verbal barrage at Stumpf, calling the embattled bank boss "gutless" and demanding he step down. Her diatribe was the most forceful condemnation yet of Wells Fargo, who fired more than 5,000 employees over the years for creating fake accounts without customer knowledge. The employees created the fraudulent accounts to meet bank quotas and were allegedly threatened with firing if they didn't comply. Hide Caption 24 of 45 Photos: Former presidential candidate Elizabeth Warren In January 2017, Warren posted this photo of her and Obama together. Obama was leaving after two terms as President. Hide Caption 25 of 45 Photos: Former presidential candidate Elizabeth Warren Warren holds a transcript of her speech in the Senate Chamber after she was cut off during the debate over Attorney General-designate Jeff Sessions in February 2017. In an extremely rare rebuke, Senate Majority Leader Mitch McConnell silenced Warren after he determined that she violated a Senate rule against impugning another senator. Warren was reading from a 1986 letter in which Coretta Scott King, the widow of Martin Luther King Jr., was critical of Sessions -- who at the time was a nominee to be a federal judge. Hide Caption 26 of 45 Photos: Former presidential candidate Elizabeth Warren Warren and other Democrats listen as President Donald Trump speaks to a joint session of Congress in February 2017. Hide Caption 27 of 45 Photos: Former presidential candidate Elizabeth Warren US Sen. Bob Corker talks with Warren during a Senate committee hearing in June 2017. Hide Caption 28 of 45 Photos: Former presidential candidate Elizabeth Warren Warren attends a confirmation hearing for Jerome Powell, who was nominated to be chairman of the Federal Reserve, in November 2017. It was a day after President Donald Trump referenced Warren as "Pocahontas" during an event honoring Navajo code talkers. Conservatives have long criticized Warren for claiming that she is part Native American, and the senator's heritage became an issue during her Senate campaigns. Trump seized on the attacks and has regularly mocked Warren by calling her "Pocahontas." In October 2018, Warren released results of a DNA test showing she has distant Native American ancestry. The DNA results claimed "strong evidence" of Native American ancestry "6-10 generations ago." But it only served to intensify the criticism given her distant ties. Hide Caption 29 of 45 Photos: Former presidential candidate Elizabeth Warren Warren runs down Boston's Clarendon Street waving to crowds during the annual Boston Pride Parade in June 2018. Hide Caption 30 of 45 Photos: Former presidential candidate Elizabeth Warren Warren and US Sen. Susan Collins ride the Senate subway in June 2018. Hide Caption 31 of 45 Photos: Former presidential candidate Elizabeth Warren Warren is seen in the sunglasses of Arian Rustemi during a rally in Boston in June 2018. Warren was calling for the swift reunification of children and parents who had been separated at the US-Mexico border. Hide Caption 32 of 45 Photos: Former presidential candidate Elizabeth Warren Warren helps Georgia gubernatorial candidate Stacey Abrams make calls to voters in October 2018. Hide Caption 33 of 45 Photos: Former presidential candidate Elizabeth Warren A Warren figurine sits in the back pocket of Mary Jo Kane during a town-hall event in Boston in October 2018. Hide Caption 34 of 45 Photos: Former presidential candidate Elizabeth Warren Warren was re-elected in 2018. Here, she is joined by her husband, Bruce Mann, as Vice President Mike Pence re-enacts her swearing-in. Hide Caption 35 of 45 Photos: Former presidential candidate Elizabeth Warren Warren, her husband and dog Bailey attend an event in Manchester, New Hampshire, in January 2019. Warren had recently announced that she was forming an exploratory committee for the 2020 presidential race. Hide Caption 36 of 45 Photos: Former presidential candidate Elizabeth Warren Warren speaks in Columbia, South Carolina, in January 2019. Hide Caption 37 of 45 Photos: Former presidential candidate Elizabeth Warren Warren looks down at the crowd in Lawrence, Massachusetts, before formally announcing her presidential bid in February 2019. Hide Caption 38 of 45 Photos: Former presidential candidate Elizabeth Warren Warren answers questions at a town-hall event in Jackson, Mississippi, in March 2019. Hide Caption 39 of 45 Photos: Former presidential candidate Elizabeth Warren Warren makes a pinky promise with 8-year-old Sydney Hansen during a campaign stop in Peterborough, New Hampshire, in July 2019. Hide Caption 40 of 45 Photos: Former presidential candidate Elizabeth Warren US Sen. Bernie Sanders grabs Warren's hand during the CNN Democratic debates in July 2019. Sanders and Warren, two of the most progressive candidates in the field, were targeted early in their debate by their more moderate counterparts. Hide Caption 41 of 45 Photos: Former presidential candidate Elizabeth Warren Warren speaks at her Super Tuesday rally in Detroit in March 2020. Hide Caption 42 of 45 Photos: Former presidential candidate Elizabeth Warren Warren acknowledges supporters as she arrives to speak to the media outside her home in Cambridge, Massachusetts, in March 2020. She had just dropped out of the presidential race. Hide Caption 43 of 45 Photos: Former presidential candidate Elizabeth Warren Warren appears on "Saturday Night Live" with actress Kate McKinnon, playing Warren, in March 2020. "I wanted to put on my favorite outfit to thank you for all you've done in your lifetime," McKinnon said. "I'm not dead," Warren responded. "I'm just in the Senate." The two then said the show's famous catchphrase, "Live ... from New York! It's Saturday night!" Hide Caption 44 of 45 Photos: Former presidential candidate Elizabeth Warren Warren asks questions during a Senate committee hearing in June 2020. She was appearing via video conference because of the coronavirus pandemic. Hide Caption 45 of 45

Can Buttigieg keep up his money game?

The breakout star on the 2019 fundraising circuit has been Pete Buttigieg, who raised nearly $25 million in the second quarter of the year, a staggering number that made the once-unknown South Bend, Indiana, mayor that quarter's top-raising Democrat.

Raising money in the third quarter has long been considered difficult -- people are on vacation, don't donate as freely and are just generally less focused on politics -- but Buttigieg's staying power will likely be judged by his ability to come close to matching his second-quarter haul.

Buttigieg, who has recently made trips to California's Bay Area and New York's Hamptons for top-dollar fundraisers, told CNN on Monday in Iowa that while he expects "to be able to be extremely competitive," he would not say he will match his second-quarter take.

"I think the expectations for every quarter are different," he said, "especially because there's such a seasonal dimension."

Photos: Former presidential candidate Pete Buttigieg Photos: Former presidential candidate Pete Buttigieg Pete Buttigieg, the former mayor of South Bend, Indiana, poses for a portrait at his office in December 2018. Hide Caption 1 of 28 Photos: Former presidential candidate Pete Buttigieg Buttigieg was an intelligence officer with the Navy Reserve from 2009 until 2017, and he served in the war in Afghanistan. Hide Caption 2 of 28 Photos: Former presidential candidate Pete Buttigieg Buttigieg thanks supporters after he was elected mayor in 2011. Buttigieg was born and raised in South Bend and went on to attend Harvard College. He later became a Rhodes scholar. After a three-year stint at the consulting firm McKinsey and Company, Buttigieg came back to Indiana and lost a race for state treasurer in 2010. Hide Caption 3 of 28 Photos: Former presidential candidate Pete Buttigieg Buttigieg listens to a question during a news conference announcing an interim police chief in March 2012. Hide Caption 4 of 28 Photos: Former presidential candidate Pete Buttigieg Buttigieg paddles a raft during the East Race Waterway in July 2013. Hide Caption 5 of 28 Photos: Former presidential candidate Pete Buttigieg Buttigieg delivers his State of the City address in February 2014. Hide Caption 6 of 28 Photos: Former presidential candidate Pete Buttigieg Buttigieg is welcomed home in September 2014 after serving a seven-month tour of duty in Afghanistan. Hide Caption 7 of 28 Photos: Former presidential candidate Pete Buttigieg Buttigieg speaks in November 2014 during a presentation ceremony for a newly redeveloped area in South Bend. Hide Caption 8 of 28 Photos: Former presidential candidate Pete Buttigieg Buttigieg speaks out about the Religious Freedom Restoration Act that was signed in Indiana in March 2015. Buttigieg and other critics of the legislation, which was signed into law by then-Indiana Gov. Mike Pence, contended that individuals and businesses could use it to discriminate against the gay community on the basis of religion. Pence later signed an amendment that was intended to protect the rights of LGBT people. Hide Caption 9 of 28 Photos: Former presidential candidate Pete Buttigieg The State Theater in downtown South Bend shows its support for "Mayor Pete" after Buttigieg came out as gay in June 2015. Hide Caption 10 of 28 Photos: Former presidential candidate Pete Buttigieg Buttigieg's name is Maltese and roughly translates to "lord of the poultry." His husband, Chasten, tweeted a list of possible pronunciations in 2018 that included "boot-edge-edge," "buddha-judge" and "boot-a-judge." Hide Caption 11 of 28 Photos: Former presidential candidate Pete Buttigieg Buttigieg speaks at a debate-watching party in Chicago in September 2016. He was stumping for Democratic presidential candidate Hillary Clinton. Hide Caption 12 of 28 Photos: Former presidential candidate Pete Buttigieg Buttigieg speaks during a Democratic National Committee forum in February 2017. Hide Caption 13 of 28 Photos: Former presidential candidate Pete Buttigieg Buttigieg greets supporters during the DNC forum in February 2017. He was campaigning at the time to be the committee's chairman. Hide Caption 14 of 28 Photos: Former presidential candidate Pete Buttigieg Buttigieg walks with Facebook CEO Mark Zuckerberg, a personal friend, who was visiting South Bend in April 2017. Hide Caption 15 of 28 Photos: Former presidential candidate Pete Buttigieg Buttigieg appears on "Late Night with Seth Meyers" in June 2017. Hide Caption 16 of 28 Photos: Former presidential candidate Pete Buttigieg Buttigieg kisses his husband, Chasten, after they were married in South Bend in June 2018. Hide Caption 17 of 28 Photos: Former presidential candidate Pete Buttigieg Buttigieg announces in December 2018 that he would not be seeking a third term as mayor. Hide Caption 18 of 28 Photos: Former presidential candidate Pete Buttigieg Buttigieg talks with a reporter in downtown South Bend in January 2019. Hide Caption 19 of 28 Photos: Former presidential candidate Pete Buttigieg Buttigieg speaks to reporters in Washington after announcing his presidential ambitions. Hide Caption 20 of 28 Photos: Former presidential candidate Pete Buttigieg Buttigieg speaks during the US Conference of Mayors in January 2019. Hide Caption 21 of 28 Photos: Former presidential candidate Pete Buttigieg Buttigieg speaks during a campaign stop in Ankeny, Iowa, in February 2019. Hide Caption 22 of 28 Photos: Former presidential candidate Pete Buttigieg Buttigieg signs copies of his book "Shortest Way Home" in February 2019. Hide Caption 23 of 28 Photos: Former presidential candidate Pete Buttigieg Buttigieg speaks on stage during the South by Southwest Festival in Austin, Texas, in March 2019. Hide Caption 24 of 28 Photos: Former presidential candidate Pete Buttigieg Buttigieg answers questions from supporters during a fundraising event in West Hollywood, California, in March 2019. Hide Caption 25 of 28 Photos: Former presidential candidate Pete Buttigieg Buttigieg and former Vice President Joe Biden talk during a break in the first Democratic debates. Hide Caption 26 of 28 Photos: Former presidential candidate Pete Buttigieg Buttigieg takes part in CNN's Democratic debates in July 2019. Hide Caption 27 of 28 Photos: Former presidential candidate Pete Buttigieg Buttigieg announces the end of his presidential campaign at an event in South Bend, Indiana, in March 2020. Hide Caption 28 of 28

A progressive or a pragmatic path?

The key question of the Democratic race, which animates the divide inside the party, is whether a progressive or a pragmatic path is the best to defeat Trump.

Conversations with Democratic voters often include dueling questions: Is the party more likely to win by reaching out to voters who supported Trump but may have buyer's remorse? Or by exciting liberals who didn't turn out in 2016?

As he did four years ago during his first presidential bid, Sen. Bernie Sanders of Vermont is leading the charge warning against incremental change. From health care to climate change to a host of other issues, the party is far closer to his views than it was four years ago.

While Biden is seen as the leading voice in the middle, other Democrats are sounding the alarm with far more urgency.

Sen. Michael Bennet of Colorado, who did not qualify for next week's debate, believes that several of his rivals are pulling the party in a dangerous leftward direction.

"There is a disconnect between where the leading candidates are and where America actually is," Bennet said in an interview Monday. "I think it's shame on us if we walk down a road this time that disqualifies us and allows him to have another four years in the White House."

Can Iowa figure out a virtual primary in a hackable world?

Iowa has a problem.

In an effort to make the state's famed caucuses more accessible and comply with Democratic National Committee rules, the Iowa Democratic Party announced early this year that it would, for the first time, allow a virtual caucus for certain people, namely those who work late, have disabilities or can't appear in person at caucuses. The program would allow these people to caucus by telephone in the days leading up to caucus day.

But months after the plan was rolled out, the DNC recommended rejecting Iowa's plan, throwing into question how the first-in-the-nation caucus state will comply with new DNC guidelines about openness without a virtual caucus.

The reason for the concern: cyberattacks. The DNC leadership does not believe a virtual caucus could be secured and worries that even the allegation of hacking could undercut the validity of the results. The DNC has been especially concerned about cyberattacks and tampering following a Russian hack effort in 2016 that led to the disclosures of emails from party leaders.

Here is what isn't going to happen: Iowa is not going to lose its first-in-the-nation status, according to numerous Democratic officials.

But the lack of clarity in Iowa will be a central story over the next several months and -- most immediately -- it has become a political story, with Democratic candidates slamming the DNC for rejecting Iowa's plan.

The most likely result is that Iowa -- and Nevada, whose plan will also be rejected but is less complicated than Iowa's -- will get a waiver from the DNC and host a more standard caucus in 2020.

What do voters actually want on health care?

The fight over "Medicare for All," an issue that has dominated the Democratic nominating battle, is just beginning, and a key question for the candidates is what voters actually want in a health care plan.

Sanders has defined the battle with his Medicare for All plan, which drew considerable coverage -- and a number of future 2020 Democratic presidential hopefuls as co-sponsors -- when it was rolled out in 2017.

But now that the race is more defined, candidates are starting to break with the Vermont independent's plan.

A slew of more moderate Democrats have outright slammed the Sanders plan. While some, like Buttigieg, have said it is a good goal, they have differed in the way to get to Medicare for All.

Then there is Harris, who, after co-sponsoring Sanders' plan, distanced herself from getting rid of private insurance and created her own plan.

One reason for the divide is polling, which shows backing for Medicare for All but a lack of support for removing all private insurance. A CNN poll released in July found that more than 8 in 10 potential Democratic voters said they favor a national health insurance plan -- but just 3 in 10 favor a plan that completely does away with private insurance.