Democratic presidential candidates have so far looked to distinguish themselves with flashy new policy proposals. Less celebrated, but perhaps just as revealing, are the past positions they've held that they're now running away from.

As candidates look to find their place in the crowded primary field and face a party electorate energized by the left, many are massaging or outright reversing old positions — and sometimes even apologizing for parts of their record that haven't aged well with voters.

While Joe Biden's long career in the national spotlight presents special challenges, just about every candidate has had to recalibrate their stances regardless of age, ideology or years in office.

Even 37-year-old Mayor Pete Buttigieg of South Bend, Indiana, who is largely building his national platform from scratch, isn't immune. In April, he announced he would no longer take donations from lobbyists and returned over $30,000 in contributions, catching up to a recent trend in Democratic politics of activists demanding a tougher stance on money in politics.

"It requires some tact and some delicacy, but folks are trying to get up to speed with where the current policies are within the Democratic Party," said Jim Manley, a longtime aide to former Sen. Harry Reid, D-Nev.

While such adjustments aren't uncommon in presidential primaries, they're also small tweaks in comparison to President Donald Trump, who frequently reverses stances with little or no explanation. But the specific ways candidates change each cycle reveals a lot about the direction of a party.

Whole lotta revamping going on

Crime and punishment is one area where a number of the contenders have been sanding down their positions and proposals.

Biden recently softened the edges of his tough-on-crime record, telling an audience at an event honoring Martin Luther King Jr. that he made "a big mistake" when he served in the Senate by backing increased penalties for certain drug crimes, including harsher sentences for crack cocaine compared with powder cocaine.

His movement on drug sentencing comes amid a broader re-evaluation of the issue: Democrats are now more concerned about mass incarceration and racial disparities in the justice system.

That shift has affected other candidates as well. Sen. Bernie Sanders, I-Vt., has been asked on the campaign trail about his vote for the 1994 Crime Bill that Biden authored. Sanders noted he criticized its emphasis on incarceration at the time, but explained he supported it because it included provisions on gun control and confronting domestic violence that he favored.

Sen. Kamala Harris, D-Calif., belongs to a later generation that was more accustomed to criticism from criminal justice reform advocates, but she has also qualified parts of her record. Harris told Pod Save America last month that a California law modeled on her district attorney policy of threatening the parents of truant children with prosecution had "unintended consequences" when other localities used it to arrest and charge offenders, something she had not done.

"I regret that that has happened and the thought that anything I did could have led to that, because that certainly was not the intention" she said.

Jess McIntosh, a Democratic strategist and former aide to Hillary Clinton's 2016 campaign, said voters might be more understanding in cases where elected Democrats, along with their constituents, had gradually evolved from one broad consensus on an issue to another.

"Almost every Democrat who was in public office in the '90s has explaining and apologizing to do when it comes to criminal justice reform," McIntosh said. "Ditto the early aughts and marriage equality."

This could include issues like marijuana legalization, which went from a fringe position when President Barack Obama took office in 2009 to almost uncontroversial today, with polls showing widespread support for it.

Former Colorado governor and Democratic presidential candidate John Hickenlooper might embody the change best: He strongly opposed a 2012 ballot initiative that made his state the first to legalize recreational cannabis. But by 2019, he had long warmed to the idea, telling a CNN town hall that Colorado's approach was "so much better than the old system where we sent millions of kids to prison, most of them kids of color."

For her part, Harris has endorsed federal legalization after previously opposing it at the state level.

While the general trend has been toward candidates aligning with party's left flank on issue after issue, there is one example where some contenders have tiptoed back to the middle: single-payer health care.

Former Rep. Beto O'Rourke supported a government-run system embodied in the "Medicare for All" bill during his Senate run in Texas last year that would effectively eliminate private insurance. But in March, after just setting out on the presidential campaign trail, he said he changed his mind and now favors legislation that would add a Medicare-like option to compete with private insurance, not abolish it. O'Rourke acknowledged that many people like their employer-provided health care insurance.

While O'Rourke is the only 2020 hopeful so far to explicitly back off on his health care position, several candidates who signed onto Sanders' single-payer bill have been emphasizing incremental approaches that would not include a ban on private insurance.

All politics is local. Until it isn't.

Several candidates are also trying to get out from under past positions that had put them at odds with the national party but were aligned with local voters, interest groups or industries in the district or state they represented in Congress.

Sen. Cory Booker, D-N.J., opposed a Democratic bill two years ago to allow less expensive drug imports from Canada, which critics argued was a sop to his state's large pharmaceutical industry. After a backlash, Booker endorsed new legislation that would open up the drug market and he swore off donations from Big Pharma. (Booker denied it was a shift, saying the new bill included better safety standards.)

Sen. Kirsten Gillibrand, D-N.Y., who was considered a relatively conservative Democrat when she represented upstate New York in the House before she came to the Senate, has repudiated some of her past positions in the bluntest terms.

In a "60 Minutes" Interview last year, Gillibrand said she was "embarrassed" by her opposition to gun safety bills and "ashamed" of her past support for proposals to scale up immigration enforcement and deny driver's licenses to undocumented immigrants. The NRA has since gone from giving her an "A" grade to an "F," and she also has come out for abolishing Immigration and Customs Enforcement and transferring its responsibilities elsewhere.

Sanders also has faced criticism from the left for sometimes voting with gun rights activists, an issue he has pointed out is viewed differently in rural Vermont. In 2016, he called for repealing a law he once supported that shielded gun manufacturers from lawsuits.

"When you represent an area and then you run nationally, things may be different in national politics than they are in a state or a region," said Simon Rosenberg, a Democratic strategist.

O'Rourke has worked to overcome environmentalists’ concerns with his record in Texas, home of a booming oil and gas industry.

He split with most in his party in 2015 by voting to lift a decades-long ban on oil exports. Environmental groups had fought the measure, and his campaign said last month that he now opposed lifting the export ban, because he lacked confidence in Trump's commitment to environmental safety. His campaign also said he had changed his mind on a 2016 amendment to restrict energy exploration off the Gulf of Mexico, which he voted against at the time. Last week, O'Rourke released a $1.5 trillion climate plan and announced he would no longer take donations tied to fossil fuel companies.

Then there's the unusual case of Rep. Tulsi Gabbard, D-Hawaii, who apologized this year for her prior activism against gay rights in Hawaii. In her case, she cited family ties: Her father was a prominent anti-gay politician who ran a group called Stop Promoting Homosexuality America.

While generations of politicians have refashioned themselves for new audiences, the current field faces some challenges previous ones did not. Thanks to the internet, political opponents have easier access to candidates' past speeches, interviews and press releases and an easy way to distribute them. Individuals can spread old clips across social media at a rapid pace.

For Democrats, though, the value of moving past potentially damaging positions and proposals may be worth it, even if it opens them up to attack.

"The right-wing media is having a field day with this, of course, but I don't think there's a good way to go about trying to get about the right side of the issues in this day and age," Manley said.