Before she announced an impeachment inquiry against President Donald Trump in September, House Speaker Nancy Pelosi worried it might provoke a backlash from voters who thought Congress had better things to do.

That didn’t happen. Instead, voters headed straight for their partisan corners: Democrats rallied behind impeachment, Republicans closed ranks behind Trump.

It’s unlikely that Pelosi ever saw impeachment winning enough converts in the Republican-controlled Senate to make Trump the first U.S. president to be removed from office. The GOP appears, if anything, more united behind Trump now than before the process began.

But the televised impeachment hearings served an unexpected purpose that should give hope to Democrats desperate to beat Trump next year.

The proceedings provided a preview of the Democrats’ most powerful argument against Trump. If you have any doubt, look at the House Intelligence Committee report released Tuesday.

It argues that Trump has abused presidential power for his own personal and political gain. He has hijacked foreign policy and obstructed justice. He has destroyed institutions and undermined alliances. He is unfit for office.

The unspoken message: Impeach first, then vote him out of office.

“Trump is facing the worst political scenario he could,” Republican strategist Mike Murphy, a frequent critic of the president, told me. “This is turning into the world’s longest campaign commercial to not reelect Donald Trump.”

Even if the Senate votes to acquit Trump in a trial, the likely outcome at this point, it could help mobilize Democratic voters next fall.

“They’ll turn out like crazy,” Murphy said. “Trump will be stuck on the defensive…. It’s a net plus for the Democrats.”

Democratic strategist David Axelrod, who helped Barack Obama win the White House in 2008, says the turmoil that constantly surrounds the president —including impeachment —may prove his undoing.

Impeachment will hurt Trump because “it adds to the overall perception of chaos that surrounds him,” he told me. “If Trump loses (in 2020), it will be because people decide that we just can’t do this for another four years.”

Axelrod warned his fellow Democrats against broadening impeachment into a collection of partisan grievances against Trump.

“The best thing Pelosi and other Democrats can do is continue to play this absolutely straight … and avoid playing into the Republican narrative that this is all a politically motivated, bloodless coup,” he said.

Pelosi and her lieutenants never planned to make impeachment part of the 2020 campaign; indeed, they spent months tiptoeing around it.

No longer. A new impeachment-focused video by House Democrats is aimed against Republicans in Congress, some of whom could be vulnerable next year if they stand by the president.

Democrats who fretted that impeachment would backfire, the way it did against Republican lawmakers who impeached Bill Clinton two decades ago, can probably breathe a sigh of relief.

In 1998, most voters didn’t think Clinton’s impeachment was warranted. This time, the public is more closely divided.

A polling average compiled by the political website Five Thirty Eight this week found that 48% of Americans favor the president’s impeachment and removal, against 44% opposed.

Almost all Democrats favor Trump’s removal, almost all Republicans are opposed, and independents are divided. About 1 in 10 voters, depending on the poll, say they haven’t decided or don’t know.

But Democrats appear more united and more intense in their feelings than Republicans. Almost half of all voters, most of them Democrats, say their view of Trump is “very unfavorable.” Only about a third say their view of the president is “very favorable.”

There are still lots of unknowns, of course. No president has ever sought reelection after being impeached. And no challenger has ever run a presidential race during an impeachment trial. Both appear likely to happen.

If the Senate holds a trial in January, before the first primaries, it will pull several candidates off the campaign trail, including Sens. Elizabeth Warren, Bernie Sanders and Amy Klobuchar.

Moreover, if the country is transfixed by a dramatic trial, the winners won’t get as much positive media attention as they normally would.

So expect jousting in the Senate over whether the trial should be fast or slow.

If the Democrats see no prospect of convicting Trump, they may seek a quick trial. If Republicans want to complicate the Democratic primaries, they may look to slow-roll it.

But once the trial ends, even a Trump acquittal may help the challenger, not the president.

That’s what some analysts believe happened in 2000, almost two years after Clinton’s acquittal. He wasn’t up for reelection, but his vice president, Al Gore, lost in a race so tight it was decided by the Supreme Court.

“The conventional wisdom is that the impeachment of Bill Clinton helped the Democrats, but my view from inside the Gore campaign is that it helped the Republicans,” Tad Devine, a strategist who worked for Gore, told me. “It allowed George W. Bush to promise that he would restore honor and dignity to the White House —and it worked.”

In the impeachment case against Trump, the jury is still out. But so far, the evidence is weighing mostly against the president, not his accusers.