With four days to go until Monday's Iowa caucuses, former South Bend Mayor Pete Buttigieg is ramping up his rhetoric and taking direct shots at two of his top rivals for the Democratic nomination, former Vice President Joe Biden and Vermont Senator Bernie Sanders.

CBS News campaign reporter Jack Turman says Buttigieg has tried to position himself as the candidate who can offer bold policy proposals while also unifying the country. His attacks on Biden and Sanders come as recent polls show him lagging behind Biden and Sanders, albeit narrowly.

"I hear Vice President Biden saying that this is no time to take a risk on someone new," Buttigieg said Thursday at a town hall in Decorah. "But history has shown us that the biggest risk we could take with a very important election coming up, is to look to the same Washington playbook and recycle the same arguments and expect that to work against a president like Donald Trump, who is new in kind." Buttigieg then pivoted to Sanders, a self-described democratic socialist who favors "Medicare for All" and free college tuition at public universities.

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"I hear Senator Sanders calling for a kind of politics that says you got to go all the way here and nothing else counts," Buttigieg continued. "And it's coming at the very moment when we actually have a historic majority, not just aligned around what it is we're against, but agreeing on what it is we're for."

Buttigieg's campaign has also recently sent out fundraising emails that say nominating Sanders would be a "risk" at a time when Democrats are desperate to reclaim the White House from President Trump.

Buttigieg has remained in the top tier of Democratic presidential hopefuls in early state polls, although his position may have slipped since the start of the year. The most recent Des Moines Register poll found him to be the first choice of 16% of likely Iowa caucus-goers while Sanders was the first choice of 20%. The same poll in November found Buttigieg leading the Democratic field in the state with 25% support.

The millennial veteran has acknowledged in recent weeks that he needs to "show versus tell" that he's the best candidate to face Mr. Trump with strong showings in Iowa and New Hampshire, which holds its first-in-the-nation primary on February 11th. He hopes that a solid finish in the first two contests will help him compete in Nevada and South Carolina, where is currently polling well behind Sanders and Biden.

While maintaining that the current campaign should not focus on re-litigating past issues, Buttigieg did reference the ongoing spat between Sanders and Biden over Social Security. The Vermont senator has accused Biden of being open to cutting Social Security in the past, a charge the former vice president's team disputes.

"This is no time to get caught up in reliving arguments from before," Buttigieg said. "The less 2020 resembles 2016 and our party, the better." After his town hall in Decorah, Buttigieg told reporters he is trying to clarify to caucus-goers what he stands for. "We're competing," Buttigieg told reporters. "It's a respectful but important competition, about what the best approach is going to be. I admire and respect everybody running for president, but we've got to make sure that we win."

Meanwhile, CBS News campaign reporter Bo Erickson notes that at a speech in Newton, Iowa, Biden spoke about the importance of 2020 Democrats focusing on Mr. Trump and not swinging at each other. The former vice president said we shouldn't "let this Democratic race slide" into negative attacks. The "temptation is too much for some" Biden added, while highlighting President Obama's comments a few months back about 2020 hopefuls avoiding a "circular firing squad."

Earlier in the day, Biden delivered a speech in Waukee, Iowa where he didn't name a single rival Democrat and kept his focus solely on the president. In the home stretch, Biden is making a similar pitch to the one he had from the start: The soul of the nation is at risk due to Mr. Trump's actions and moral turpitude.

FROM THE CANDIDATES

JOE BIDEN

As Joe Biden goes up on the air in Nevada with several new ads in a buy totaling $167,503 this week, per Kantar CMAG data, the former vice president's campaign is also rolling out several new endorsements in the state, according to CBS News campaign reporter Alex Tin. Among them are two former Clark County party chairs, the vice president of the Washoe County School District Board of Trustees, and online betting CEO Joe Asher, who was listed last year as a top fundraising bundler for Biden.

MICHAEL BLOOMBERG

Thursday Democratic presidential candidate and former New York Mayor Michael Bloomberg released his Super Bowl Ad, in a spot that the campaign says "highlights the urgent need to prevent gun violence in America," according to CBS News Campaign Reporter Tim Perry.

The 60 second spot, titled "George," will air Sunday February 2 during Super Bowl LIV. It features the story of Calandrian Simpson Kemp, a mother whose son, George Kemp Jr., was shot and killed in 2013.

In the aftermath of her son's death, Kemp has been an active member of Moms Demand Action. "I chose to devote the entire sixty-second ad to gun safety because it matters to communities across the country and it will be a top priority for me as president," Bloomberg said in a statement released by the campaign.

"Calandrian's story is a powerful reminder of the urgency of this issue and the failure of Washington to address it. People will be rooting for different teams in the Super Bowl, but virtually all Americans — including people in both parties and a majority of gun owners — support universal background checks and other common sense gun laws."

Bloomberg, a billionaire businessman, has used his enormous fortune to self-fund his campaign. Despite a late entrance into the race and his decision to skip the first four voting states, including Iowa where voting begins Monday, Bloomberg is on track to spend more than $275 million on television, radio and digital ads by the end of the week.

PETE BUTTIGIEG

Equality California, the state's largest LGBTQ civil rights organization, and its recently-launched Nevada partner Silver State Equality announced Thursday they would be backing Pete Buttigieg after an unanimous vote by the groups' endorsement committee. CBS News campaign reporter Alex Tin says the former South Bend mayor can use all the help he can get as early voting kicks off in California, where Buttigieg has failed to crack double digits in recent polls of the Super Tuesday contest.

"While we did not endorse Mayor Pete simply because he's gay, the historic nature of his candidacy has already had a transformational impact on the LGBTQ community," Rick Zbur, the groups' executive director, said in a statement, also praising Elizabeth Warren and Tom Steyer for their "extremely strong" platforms.

TULSI GABBARD

Congresswoman Tulsi Gabbard's long-shot campaign for the presidency is betting big on a strong performance in New Hampshire, where the primary historically rewards outsiders and underdogs, on occasion. Over 42% of the state's voters here are registered as "undeclared," which allows them to vote in either party's primary in February. And while other candidates focus on next week's Iowa caucuses, Gabbard has all but moved to New Hampshire, spending more days in state (a sum total of 34) than any other Democratic candidate across December and January.

A recent analysis by the New York Times reveals just one-fifth of Obama-Trump voters returned to the Democratic Party in the 2018 midterm elections, while three-quarters voted Republican. Roughly half of the New Hampshire towns Gabbard has visited backed Mr. Trump in 2016. Her populist, anti-war message attracts fans from both ends of the political spectrum, including former Trump strategist Steve Bannon and former Democratic Ohio Congressman Dennis Kucinich. But she has struggled to attract much of any support from mainstream Democratic voters who pick their party's nominee.

"[S]he's pulling from Trump voters. It could make it even tougher for Trump to win, particularly in states like Michigan and New Hampshire," Bannon told CBS News campaign reporter Nicole Sganga.

BERNIE SANDERS

Bernie Sanders' first TV ads to air in Super Tuesday states are up today in California and Texas. In a 30-second ad aired in Dallas and Los Angeles this morning for the first time, Sanders talks about the rich getting tax breaks while the middle class continue to struggle. "That's what happens when billionaires are able control the political system," Sanders says on camera.

CBS News political unit associate producer Sarah Ewall-Wice says he goes on to talk about his campaign being funded by the working people and says those are the people he will represent. In another ad aired in Dallas and San Francisco, a narrator talks about Sanders fighting to raise wages and for health care.

"Our country is at a turning point. Hard working people betrayed by Trump struggling to survive," the narrator claims. "In this moment, we need a fighter. Bernie Sanders, we know he'll fight for us as president because he always has," the voice concludes. According to Kantar/CMAG tracking, Sanders is on track so far to spend $1.5 million in California and more than $160,000 in Texas through February 25th, but more ad buys are likely. On Tuesday, the campaign announced it would me making $2.5 million in ad buys in the two states this week. Super Tuesday is March 3rd.

PRESIDENT TRUMP

The Trump Campaign released one of two ads set to air during the Super Bowl on Thursday, reports CBS News political unit associate producer Eleanor Watson. The 30-second ad released Thursday morning called "Stronger, Safer, More prosperous" highlights the record unemployment numbers the United States has seen during the first three years of the Trump administration. According to the campaign, the other 30-second ad will not be released prior to the game.

ANDREW YANG

With the Iowa caucuses quickly approaching, rumors are swirling around Des Moines about campaigns making alliances if their candidate doesn't hit the 15% viability threshold. "I think some campaigns have reached out to our team," Andrew Yang told reporters at an event yesterday, CBS News political correspondent Ed O'Keefe reported.

A source close to the Yang campaign with knowledge of the situation tells CBS News campaign reporter Adam Brewster that former Vice President Joe Biden's campaign reached out about a deal. The rules of the Iowa caucuses require candidates to have 15% support in a room to win delegates, meaning some people have to settle for their second or third choice. Yang said yesterday that he isn't inclined to instruct his supporters where to go if he doesn't enough support in a caucus room. "I frankly think I'd have a hard time getting them to do anything that they're not naturally inclined to do," Yang said. In Waukee today, Biden ignored questions about whether his campaign is trying to make deals with other campaigns and one of his top surrogates, former Iowa Governor Tom Vilsack, also sidestepped questions on the issue, according to O'Keefe.

STATE-BY-STATE

GEORGIA

A popular clergyman has announced his bid to run as a Democrat in the special election for U.S. Senate in Georgia. CBS News political unit associate producer Eleanor Watson reports that Reverend Ralphael Warnock, the pastor of Martin Luther King Jr.'s Ebenezer Baptist Church, announced his U.S. Senate bid Thursday in a Twitter video. Warnock is the first high-profile candidate to enter the race.

Matt Lieberman, the son of former Senator Joe Lieberman, and Ed Tarver, a former attorney, are also competing for the Democratic nomination. Nevertheless, Warnock's entry could rally Democrats ahead of a fight with what may be a divided Republican Party in the Peach State.

The special election is being held to fill the seat held by former Senator Johnny Isakson, who resigned at the end of last year. Governor Brian Kemp appointed financial executive Kelly Loeffler to Isakson's Senate seat following his resignation at the end of 2019. Loeffler will run in the special election in November to carry out the final two years of Isakson's term, and she has the support of the National Republican Senatorial Committee and the Senate Leadership Fund. However, Congressman Doug Collins announced his bid for the seat on Wednesday, setting up what could be a bitter primary fight within the GOP.

Democrats are targeting a number of House seats in Georgia, as well as the state's two Senate seats. Georgia has been a Republican stronghold for decades, but Democrats hope the state's changing demographics could help them win it back this year.

CONGRESSIONAL COVERAGE

IN THE HOUSE

The House Democrat campaign arm is confident in using healthcare as their central message for 2020, but didn't specify any immediate plans for any specific ads in some of the most competitive districts they have to defend, reports CBS News political unit broadcast associate Aaron Navarro.

In a meeting with reporters on Thursday, Democratic Congressional Campaign Committee Chair Cheri Bustos detailed the party's million-dollar national cable ad buy, which is meant to "set a dialogue" about healthcare and the Senate's inaction on the House's H.R. 3 bill, which aims to lower prescription drug prices.

The ads will run in 14 cable markets across the country, including in areas that overlap with competitive Democrat districts. Bustos pointed to good fundraising numbers from 2019 and the length of the election cycle, as to why no district-specific ads are currently being run. "Let's just remember the election is nine months off," Bustos said. "We want to make sure that going into November 2020, we've got everything we've got at our disposal when people are paying very close attention and making those decisions of who they're going to vote for."

Despite setting their own off-year record, the Republican campaign arm was outraised by the DCCC by more than $40 million in 2019, and vulnerable Democratic members raised $92 million in the off year. Two such members, Joe Cunningham of South Carolina and Anthony Brindisi of New York, both released their first 2020 ads this week, one of the first direct responses in these districts to months of ads from outside Republican groups about impeachment.

Bustos, a Democrat from a district won by Mr. Trump, said any member being targeted by outside ads should run on their records, and listed off a number of Democrats she says have compelling arguments. "They've got the stories to tell they're getting the job done. Cindy Axne's done 57 town hall meetings, Joe Cunningham has closed more than 1,500 cases…Lauren Underwood working to bring down the cost of insulin," she said. "When you see somebody going after you, you can also use that as motivation. And I think they're doing that, but they're doing all the right things."

Bustos also said after he dropped out, Beto O'Rourke reached out to the DCCC offering his help if needed. The DCCC themselves have reached out to several former presidential candidates, such as Senators Kamala Harris and Cory Booker and Secretary Julian Castro, about potential involvement in the House election cycle. "Where ever it makes sense, you bring people in where they're going to resonate well," she said.