After bruising defeats in Virginia, New Jersey, and Alabama, Republicans are bracing for the possibility that Democrats take back the House in 2018—and Democrats, after a year in the wilderness, are beginning to seriously debate the political ramifications of impeaching Donald Trump if they do. For months, the Democratic base has been agitating for leadership to take more aggressive steps to censure the president. Until now, the idea of impeaching Trump has taken a backseat to more prosaic concerns. But if Democrats take back the House, that conversation will quickly enter the mainstream—as will the attendant political risks.

Democratic leadership has been wary of having that conversation too early. As soon as Democratic lawmakers began floating the possibility of Trump’s ouster, House Minority Leader Nancy Pelosi moved to shut down the discussion. “What are the facts?” the California lawmaker said during an interview with CNN last May. “If you don’t have that case, you’re just participating in more hearsay.” Despite leadership’s best efforts to stymie impeachment rumblings, they have endured on Capitol Hill. As Robert Mueller’s probe has drawn closer to the president, public support for removing the president from office has reached an all-time high, according to recent Democratic polling.

The fervor on the left has been fueled in part by Democratic activists and donors who have put the impeachment issue front and center, to Pelosi's consternation. At the forefront has been Democratic mega-donor Tom Steyer, who has spurred support for Trump’s impeachment with the launch of his digital petition campaign, NeedToImpeach.org. Politico reports] that through a combination of traditional television spots and grassroots campaigning, Steyer has collected nearly 4 million digital signatures and incited a fresh wave of support for Trump’s ouster among the Democratic base. “We have tapped into something much larger than we thought,” Steyer said in a recent C-SPAN interview. The success of the campaign has even prompted speculation that Steyer, who has drawn the ire of President Trump, might run in 2020.

On Capitol Hill, there is growing support for Trump’s impeachment. Earlier this month, 58 House Democrats voted to begin debate on articles of impeachment against Trump after Representative Al Green of Texas introduced a resolution on the floor. “I think a lot of the base would push strongly for impeachment. I think many of us feel like the lines have been crossed,” California Representative Jared Huffman told Politico.

Others, however, urge caution, highlighting the backlash the Republican Party faced after the G.O.P.-led House voted to impeach Bill Clinton in 1998. “Impeachment, it’s not something you ought to welcome. It’s not something you ought to be ready to—it’s not something you want,” New York Representative Jerry Nadler, who was elected as the top Democrat on the House Judiciary Committee—where any impeachment proceedings would begin—said in an interview with Politico. “If we were in the majority and if we decide that the evidence isn't there for impeachment—or even if the evidence is there [and] we decide it would tear the country apart too much, there's no buy-in, there's no bipartisanship and we shouldn't do it for whatever reason—if we decide that, then it's our duty to educate the country why we decided it.”

There is a fear among Democrats that any partisan move against Trump would backfire. “Winning the House shouldn’t be seen as a referendum one way or the other on the question of impeachment. To insist otherwise calls into question the credibility of the entire effort,” Virginia Representative Gerry Connolly told Politico. “I think that is a huge mistake and a pitfall at all costs to be avoided.” He continued that an effort to impeach Trump should be driven by facts. “I take an oath to the Constitution of the United States, and this is a constitutional process,” he added.

The concern that any effort to impeach Trump would be seen as partisan and interpreted as an example of Democrats being obstructionists is particularly strong among Democrats representing districts Trump beat Hillary Clinton in last year. “People in a swing district—I’m literally a 50-50 district—they just want us to get something done,” Representative Cheri Bustos of Illinois said. “If we win back the majority and we don’t stay focused on what people want us to stay focused on, that majority will be short lived.”