It was a battle for the soul of the Democratic Party on stage in Motor City.

Sens. Bernie Sanders and Elizabeth Warren -- the presidential primary field's liberal standard-bearers -- were pulled into what was essentially a two-and-a-half-hour fight with their more moderate rivals Tuesday night at the second round of Democratic nomination debates.

RYAN, SANDERS CLASH ON CLIMATE CHANGE: 'YOU DON'T HAVE TO YELL'

The result was the party's divide on full display, with the center-left (and lower-polling) contenders fiercely arguing that policies like "Medicare-for-all" and the Green New Deal will "FedEx the election" to President Trump, and the higher-profile candidates on the left flank just as fiercely arguing that their policies are the kind of bold solutions America needs.

Their frustration mounted, with Sanders at one point firing back at Ohio Rep. Tim Ryan for claiming the Vermont senator didn’t really know “Medicare-for-all” would provide coverage better than the current plans Americans would lose if the country moved to a single-payer system.

“I do know. And I wrote the damn bill,” Sanders snapped.

Former Maryland Rep. John Delaney, who elbowed his way into claiming considerable airtime during the Detroit debate, charged at another point: "I think Democrats win when we run on real solutions, not impossible promises."

Warren shot back: "I don't understand why anybody goes to all the trouble of running for president of the United States just to talk about what we really can't do and shouldn't fight for."

The line drew loud applause from the room and crystallized the broader debate in the Democratic primary right now, as many in the field gravitate toward liberal policy positions amid warnings from other candidates about the implications for the November 2020 general election.

"That is a disaster at the ballot box. You might as well FedEx the election to Donald Trump," former Colorado Gov. John Hickenlooper charged, in reference to the notion of guaranteeing jobs under the Green New Deal or taking away private insurance under Medicare-for-all.

For their part, Sanders, I-Vt., and Warren, D-Mass., largely avoided sparring with each other, maintaining a virtual truce that's been in place on the campaign trail. Both sought to keep focus trained on Trump. Sanders lobbed a litany of insults at the president throughout the debate, labeling him a sexist, a racist, a xenophobe and a "pathological liar."

But they were repeatedly pulled into the scrum by their on-stage rivals.

With the Democratic National Committee raising the thresholds for the third and fourth rounds of debates -- in September and October -- the showdowns this week may be the last chance for many of the lower-tier candidates to make a splash in front of a prime-time national audience.

And they didn't miss the opportunity, taking repeated punches at Sanders and Warren over their strong support for a government-run single-payer health care system that would eliminate private insurance.

Some of the biggest fireworks broke out right off the bat in the CNN-hosted debate.

Even before the questioning got underway, Delaney took aim at both of them – arguing in his opening statement that “we can go down the road that Senator Sanders and Senator Warren want to take us, with bad policies like Medicare-for-all, free everything and impossible promises that will turn off independent voters and get Trump re-elected.”

Minutes later, Sanders succinctly responded to Delaney's criticism, telling him “you’re wrong.”

Warren joined Sanders in defending Medicare-for-all, chastising their critics.

“Let’s be clear about this. We are the Democrats. We are not about trying to take away health care from anyone. That’s what the Republicans are trying to do,” she said to applause from the crowd.

Delaney was joined by many of the other centrists, however, in taking aim at Sanders and Warren.

Hickenlooper said that “last year Democrats flipped 40 Republican seats in the House, and not one of those 40 Democrats supported the policies of our front-runners at center stage.”

And Montana Gov. Steve Bullock, making his debate debut, also took aim at Medicare-for-all, emphasizing that “at the end of the day I’m not going to support any plan that rips away quality health care from individuals. This is an example of wishlist economics. It used to be Republicans who wanted to repeal and replace [ObamaCare]. Now we have Democrats as well."

The contenders also disagreed over decriminalizing illegal crossings over the U.S. southern border with Mexico, a combustible issue.

South Bend, Ind., Mayor Pete Buttigieg explained that these crossings would still be illegal.

But Bullock later warned that those calling to decriminalize illegal immigration are "playing into President Trump's hands."

Ryan later suggested Sanders' plan would incentivize illegal immigration, adding: "If you're going to come into the country, you should at least ring the doorbell."

Former Rep. Beto O’Rourke of Texas, who’s made the issue of illegal immigration central to his White House bid, highlighted that he’d waive citizenship fees, reform deportation laws, and resume aid to Central American countries to prevent the flow of families trekking toward the U.S.

Both Sanders are Warren argued that families arriving at the southern border should not be treated as criminals. Taking aim at the Trump administration’s current policy toward migrants trying to cross the border, Warren stressed "I've seen the mothers, I've seen the cages of babies…We must be a country that every day lives our values and that means we cannot make it a crime when someone comes in."

While candidates like O'Rourke were looking for a breakthrough to reinvigorate their campaigns, the debate was dominated throughout by the clash between Sanders and Warren on one side and the center-left candidates on the other.

Buttigieg at one point cautioned everyone on stage that "it is time to stop worrying about what the Republicans will say," claiming the GOP will label them "a bunch of crazy socialists" no matter what.

And Sen. Amy Klobuchar of Minnesota – another of the more moderate contenders – asked: “Do I think we’re going to end up voting for a plan that takes half of America off their insurance in four years?”

Answering her question, she said, “No I don’t think we’re going to do that.”

Best-selling spiritual author and progressive activist Marianne Williamson – who’s spotlighted racial reconciliation a centerpiece of her campaign – focused on the water crisis in nearby Flint, Mich.

The city made headlines in 2014 due to lead contamination in Flint’s water.

"Flint is just the tip of the iceberg," Williamson said as she highlighted the broader issue of the country’s racial inequalities. She argued Flint’s woes would not have happened in nearby Grosse Pointe, a majority-white affluent Detroit suburb where the candidate raised her daughter.

"If you think any of this wonkiness is going to deal with this dark psychic force of the collectivized hatred that this president is bringing up in this country, then I'm afraid that the Democrats are going to see some very dark days," she said.