Everyone has a theory about the impeachment of the President, but everyone cannot be right. Right now, though, Donald Trump and House Speaker Nancy Pelosi — two people who don’t appear particularly fond of each other — seem to be in agreement that if House Democrats were to impeach the President, it would work out well for him.

“He wants to be impeached, so he can be exonerated by the Senate,” Pelosi told a meeting of Democrats on Thursday. And the Associated Press reports that in the White House, that’s exactly what they are hoping for:

“As the subpoenas have flown in recent weeks, White House officials have adopted a quasi-official policy of trying to goad Democrats into impeachment. Trump has ordered his administration to stop complying with House Democrats’ probes, stonewalling efforts across the board while challenging the legislative body’s basic constitutional role of oversight. His intransigence has animated more and more Democrats to talk impeachment, even if just to begin proceedings in order to get further access to documents and testimony.

“White House aides believe that Pelosi cannot withstand the clamour from her rank-and-file to impeach Trump, and believe that when Democrats take that step, it will assure Trump’s re-election.”

But just because that is what they believe in the White House, it does not mean they are right — especially this White House, which is not exactly filled with the best and the brightest. There is a temptation to assume that if the other side is pursuing some kind of counterintuitive strategy, then it must have a good reason, and one should not fall into its trap.

But here’s the truth: no one knows what the political effects of impeachment will be. Not Pelosi, not Trump, not any Democratic or Republican “strategist” you see on cable news, not any pollster, not any elected official, not any political scientist, not any journalist and not your loudmouth uncle. No one.

As everyone considers this question, we have some evidence we can use to inform our thinking, but that evidence doesn’t prove anything. For instance:

• On one hand, Bill Clinton was impeached and Republicans didn’t do as well in the 1998 election as they might have otherwise. On the other hand, he was impeached because of a consensual affair and Republicans still won the White House in 2000, whereas Trump has left a trail of misconduct and malfeasance a mile long. And don’t forget that Clinton was extremely popular at the time, while Trump is extremely unpopular

• On one hand, polls show most Americans don’t think Trump should be impeached, at least not yet. On the other hand, when the Senate began the Watergate hearings, most Americans thought it wasn’t a serious matter; the investigation showed them why Richard Nixon had to go

• On one hand, Trump will inevitably be found not guilty by the Senate, which will allow him to declare that he has been exonerated. On the other hand, the process will shine a light on his wrongdoing, making his misdeeds clear for all to see

• On one hand, impeachment could anger and energise members of the Republican base, boosting their turnout in the 2020 election. On the other hand, impeachment would show members of the Democratic base that their representatives are serious about holding Trump accountable and remind them of why they hate him, boosting their turnout

• On one hand, impeachment could seem like a distraction from “getting things done”, which voters say is something they want. On the other hand, Republicans have proved time and again that voters don’t punish a party for not getting things done, being too partisan or mounting too many investigations

• On one hand, Trump thrives on conflict and chaos, so impeachment could be great for him. On the other hand, the idea of impeachment is clearly driving him batty, making it likely that he will become increasingly erratic and convince the public that he isn’t fit for the job

What do we learn from all these contradictory bits of evidence and logic? Out of them you could construct a perfectly reasonable political argument for or against impeachment.

The central problem is that while history and existing conditions can give us hints about how impeachment might turn out, we just cannot know for sure, and those who say they can predict what would happen are fooling themselves. That’s the thing about politics: it is inherently unpredictable, and the past is only a partial guide to the future. Things that have never happened before happen all the time.

Let’s not forget that a reality-show buffoon and famous con artist is right now the most powerful person on Earth because of a series of unusual events almost no one saw coming. In the Trump era, no wise person can predict anything with absolute certainty.

There is a more agnostic position that Democrats could take on this issue: impeachment might be good for Trump or it might not, but we’ve been winning in the courts in our attempts to pry information out of him despite his attempts at obstruction, and we’re drawing the noose tighter around him, so why take the chance? That’s reasonable, too, but it is a political assessment, not a substantive one.

Which leaves us with this: the judgment should be made on the merits. If you think Trump’s conduct merits impeachment, that is what you should support. I have yet to hear a single Democrat argue that it would be wrong to impeach Trump; those who don’t want to do it think it is politically misguided, but almost none of them believes he doesn’t deserve it.

That’s another thing about the uncertainty of politics: sometimes doing the right thing hurts you, and sometimes it helps you. You might not be able to tell in advance. So why not make the choice you can be proud of?

• Paul Waldman is an opinion writer for The Washington Post’s Plum Line blog