Although talk of a “blue wave” has been tempered recently by a tightening of the generic congressional ballot, Democrats remain giddy at their prospects of taking back control of one or both chambers of Congress in this fall’s midterm elections. They should be careful what they wish for.

To capture the House of Representatives, Democrats need to pick up 24 districts now held by Republicans. Strong recruitment and campaign fundraising have put enough seats across the country in play for Democrats to bring winning the lower chamber within reach. In the Senate, they only need a net gain of two seats, a goal that actually appears to be the tougher task given how much the map favors Republicans this year—only eight GOP-held seats are on the ballot this year, compared to some two-dozen Democratic states. Moreover, 10 of those Democratic seats are in states carried by Donald Trump in 2016.

But Democrats should really hope they don’t win a critical mass anyway. Why?

For starters, they still wouldn’t be able to get much done in the way of legislation. Even if Democrats were to ride a huge wave in November and win back both chambers, they’d face the same problem Republicans have now: majorities so slim as to be unmanageable. Even with iron discipline and complete unity, any Democratic legislation would be blocked by Republican Leader Mitch McConnell in the Senate, who would suddenly rediscover his previous love affair with the filibuster. If that didn’t work, President Trump would be waiting in the wings with his veto pen. At best, a takeover of the Senate would allow Democrats to stall Trump’s march toward packing the federal judiciary with conservative judges.

By winning back the House, however, Democrats would take control of committees. This sounds good until you realize that the new Judiciary Committee chair would be under immediate pressure from the party’s liberal base to begin impeachment proceedings against Trump. Democratic leaders Chuck Schumer and Nancy Pelosi would have great difficulty stemming this tide, because this is exactly what the vast majority of the base of their party wants: 76 percent of Democrats want their lawmakers to “begin the impeachment process against President Trump” if they win back control of the House of Representatives, according to a Quinnipiac University poll taken last month.

Here, history would be repeating itself, and not in a way that suggests a good outcome for Democrats. The problem, just as it was in 1998 when Bill Clinton was president, is that the country as a whole is against the idea. Pelosi has done a delicate dance for the past 13 months trying to tamp down impeachment talk among her most progressive members. Despite her efforts, in December 58 Democrats voted to lay out articles of impeachment against the president.

If Democrats win the House majority, it’ll be much harder for Pelosi to stem this tide among her members. If the House did vote to impeach, unless convincing evidence was presented of Russia-related wrongdoing or some other criminal conduct on Trump’s behalf, Democrats could never get the two-thirds majority needed in the Senate to remove him. They would effectively turn the president into a victim in almost the same way Republicans did to Clinton.

In other words, Democrats retaking control of one or both chambers of Congress would most likely boost Trump’s prospects in 2020 by giving him something (and someone) to run against. Right now, railing against Democrats in a Republican-controlled Congress is not a terribly effective weapon in Trump’s arsenal. But to be able to tweet broadsides against Pelosi for two solid years and blame her for all manner of ills heading into 2020 would be a vastly more potent line of attack.

As counter-intuitive as it seems, Democrats would be better off gaining seats in the House but coming up just short of retaking control. The benefits of losing are substantial. It would keep their base angry and fired up heading into 2020 while at the same time not giving Trump’s base a reason to get re-energized. In addition to keeping impeachment from dominating the news, not retaking the House this November could serve as the tipping point for Democrats to push the current leadership aside and usher in a new generation of young, fresh, dynamic members to lead the party into 2020 and beyond – something many believe the party desperately needs.