Days after suffering stunning and sweeping presidential and congressional defeats, the Democratic Party faces the challenge of repairing internal turmoil while mounting an appropriate response to an unpredictable but inevitable four-year battle against President-elect Donald Trump.

While President Obama and others immediately called for unity after a notoriously divisive election, the party’s forward-looking message has since become more nuanced: Your move, Donald.

“We’re going to stand up and say there’s a lot we’ll try to work with you on, there are a lot of places where there are going to have to be compromises,” Massachusetts Sen. Elizabeth Warren said Thursday on MSNBC. “But on those core issues about treating every single human being in this country with dignity, on that we stand up and we fight back. We do not back down. We do not compromise, not today, not tomorrow, not ever.”

In his first tweet since Election Day, Georgia Rep. John Lewis, the civil rights icon, made a subtle reference Friday to his signature rallying cry for activism, using the hashtag #goodtrouble. Vermont Sen. Bernie Sanders, who lost to Hillary Clinton in the Democratic primary, has alternated between a wary willingness to work with Trump on populist economic issues and a promise to oppose his racist and sexist rhetoric—and any policies that come as a result.

“If Donald Trump takes people’s anger and turns it against Muslims, Hispanics, African Americans and women, we will be his worst nightmare,” Sanders warned Thursday, while also calling for reform to the Democratic Party, which he said “has to be focused on grassroots America and not wealthy people attending cocktail parties.”

But it was retiring Senate Minority Leader Harry Reid who sent the strongest message to the future president, placing the responsibility of reconciliation squarely on his shoulders.

“If this is going to be a time of healing, we must first put the responsibility for healing where it belongs: at the feet of Donald Trump, a sexual predator who lost the popular vote and fueled his campaign with bigotry and hate. Winning the electoral college does not absolve Trump of the grave sins he committed against millions of Americans. Donald Trump may not possess the capacity to assuage those fears, but he owes it to this nation to try,” Reid said in a statement on Friday. “If Trump wants to roll back the tide of hate he unleashed, he has a tremendous amount of work to do and he must begin immediately.”

At the same time, Democrats are considering the best next step for their own leadership, amid criticism that the party lost a winnable high-stakes presidential election. Former Maryland Gov. and presidential candidate Martin O’Malley and Minnesota Rep. Keith Ellison are among those in the running to replace interim Democratic National Committee chair Donna Brazile, as is former Vermont Gov. Howard Dean.

“We need somebody to represent us in the fights which are inevitable in the next four years,” Tad Devine, a longtime Democratic strategist who served as senior adviser to Sanders’ presidential campaign, told Fortune. “And that will be fights over whether or not we have a broad and inclusive society or whether Trump falls back to the rhetoric that got him elected, which was the opposite of inclusion.”

As the party looks to avoid a similar outcome in future elections, it will need to expand its geographic reach, reconsider the role of the DNC in the nomination process and work to excite more people, especially young people, Devine said.

“I also think that the issues that we run on are really important, and Donald Trump really sort of reached into the bag of the Democratic Party on some issues—issues like trade, for example, and also talking about massive investments in infrastructure that create jobs,” Devine said. “We can’t let the Republicans steal those issues from us.”

If Trump pursues those issues—investing in infrastructure, creating millions of jobs and working on trade policies that keep jobs in the country—Devine predicts Democrats will work with him.

“If, instead, he wants to ban Muslims from coming to America or spend time and resources trying to build an impenetrable wall, I don’t think he’s going to get a lot of support form Democrats,” Devine said. “It’s frankly going to be up to him.”