The 2020 Democratic presidential candidates agree on a few goals: Expand access to health care and education, address climate change, beat President Trump.

But how to do all that is where the primaries start to gets messy. The following questions have created friction within the party, and the Democratic debates Wednesday and Thursday could get confrontational if they come up.

Should Democrats play nice with Republicans or be antagonistic to them?

Former vice president Joe Biden has argued that civility is what the country needs after four years of Trump.

“Some say Democrats don’t want to hear about unity, that they are angry, and the angrier you are, the better,” Biden said at his campaign kickoff rally. “Well, I don’t believe it. I really don’t. I believe Democrats want to unify this nation."

Don’t be so naive, some of his opponents argue. Republicans have blown up previous political norms — holding up President Barack Obama’s Supreme Court pick for a year, refusing to take the allegations against Trump in the Mueller report seriously. So let’s play hardball right back. “We’re done with two sets of rules, one for the Republicans and one for the Democrats,” Sen. Elizabeth Warren (D-Mass.) has said, suggesting getting rid of the filibuster rule that requires 60 votes to pass legislation in the Senate.

Should Democrats champion socialism?

Americans want and deserve more from their government than they’re getting under Trump, so let’s lean into bold socialist-style programs, such as getting rid of most private insurance in favor of putting everyone on Medicare, some of the 2020 Democrats argue.

“If there was ever a moment when we needed a new vision to bring our people together in the fight for justice, decency and human dignity, this is that time,” Sen. Bernie Sanders (I-Vt.) said in a speech recently. He’s the only candidate directly championing socialism, but a lot of his 2020 opponents have signed on to efforts such as Medicare-for-all.

No way, say other candidates. “Socialism is not the answer,” former Colorado governor John Hickenlooper has said. “If we’re not careful, we’re going to end up reelecting the worst president in American history.” Notable: Hickenlooper will be on the debate stage with Sanders.

Is Joe Biden out of touch with today’s Democratic Party?

If it sounds as if we are singling out Biden, it’s because we expect his opponents to do the same. He’s been leading in all major polling since he got into the race, and the quickest way for candidates to get noticed in these unruly debates will be to throw punches at him.

Some of them have already started. Over the past few weeks, Biden has been on the defensive about his support for the Hyde Amendment prohibiting federal funding for abortion, for his role in passing a 1994 tough-on-crime bill and for talking about how he was close with segregationist senators in the ’70s.

On much of this, Biden has quickly tried to adjust to be more in line with the liberal wing of the Democratic Party. But he’s bristled at some characterizations from his opponents, such as from Sen. Cory Booker (D-N.J.), that he should apologize for his friendliness with segregationist senators. “Apologize for what?” he said.

Expect his opponents to continue to make the case that Biden is out of touch with the values of today’s Democratic voters.

Who’s most electable against Trump?

This is a major question, and a vexing one, for Democrats. The problem is that “electability” is a subjective term that Democratic voters haven’t quite settled on a meaning for.

This debate is rife with gender and racial bias, such as: Should Democratic voters nominate a man after seeing Hillary Clinton lose to Trump? Is it too risky to nominate a person of color, given that Trump’s election appeared to be, in part, a backlash against Obama?

The “electability” question also encompasses a candidate’s political strategy.

Biden has argued that he’s most electable because he can talk to middle-class voters in states Trump won, such as Pennsylvania.

Sanders has argued that he’s most electable because he’s leading a grass-roots movement to take on the billionaire class. “We defeat Trump by running a campaign of energy and enthusiasm that substantially grows voter turnout,” he’s said.

Sen. Kamala D. Harris (D-Calif.), a former prosecutor, says she can win because she can call Trump like she sees it: “We need somebody on our stage when it comes for that general election who knows how to recognize a rap sheet when they see it and prosecute the case,” she said recently.

Sen. Amy Klobuchar (D-Minn.) says she can win because she’s won tough races before: “I know how to win."

What’s the best way to take on Trump?

Just like there’s no consensus on how to build a political coalition to beat Trump, there’s no consensus on how to engage with Trump.

Democrats know Trump is going to call them names and say false things. Do they call him names right back? Ignore him? Try to fact-check him like Clinton did in one of her debates? Keep their heads down and focus on their policy ideas?

This point of contention will probably be more subtle than the others, but the Democratic candidates onstage are going to want to show voters how they would handle Trump if they end up on a debate stage with him next year.