WASHINGTON — House Speaker Nancy Pelosi said Thursday she believes President Trump “has been involved in a criminal cover-up.” Too bad she’s not in a position to do something about it.

Oh wait, she is. If she truly believes the president has committed crimes, if she truly believes he has violated his oath of office, if she truly believes he is trampling the Constitution, she can have the House begin a formal impeachment inquiry. But she won’t.

When Pelosi says that most House Democrats do not favor launching a process that could lead to impeachment, she’s telling the truth — but not the whole truth. She is the respected and unchallenged leader of her caucus. If she were to change her mind, a lot of other minds would quickly follow.

Pelosi clearly believes impeachment is a political trap, and she may be right. But doing nothing looks increasingly like a political trap, too, which means the speaker is going to have to pick her poison. In politics, observation suggests, it is generally better to play offense than play defense. And in life, conscience demands, it is always best to do what you know is right.

The danger in doing nothing is simply that Congress is allowing Trump to hold himself above the law. Trump’s attorneys formally made that argument this week in a court filing that seeks to bar the House Committee on Oversight and Reform from investigating whether Trump committed tax fraud. But Trump’s “Sun King” view of the presidency has been glaringly obvious all along. He treats legal and constitutional norms like doormats and acts as if the powers of the presidency are unlimited.

This is not “what the American people voted for,” as I’ve heard Republicans argue. Many voters indeed wanted a wrecking ball, a disrupter. They did not want to weaken our democracy by giving the president the unchecked powers of a banana republic strongman.

And even if that is what some Trump voters want, they can’t have it. Congress has a sworn duty to uphold the Constitution, which makes clear that everyone, including the president, is subject to the law.

There was much gnashing of teeth and clutching of pearls over Trump’s declaration, in an interview broadcast Wednesday, that hypothetically he would accept help from a foreign government in his upcoming reelection campaign. Democrats and Republicans alike felt obliged to declare that they would never, ever do such a horrible thing. But Trump explicitly solicited and welcomed help from Vladimir Putin’s Russia in the 2016 election. If the idea of such foreign meddling is so shocking, why doesn’t the established fact of such meddling deserve official sanction?

Pelosi says she accepts the ample evidence, as reported by special counsel Robert Mueller, that Trump obstructed justice. She says the president is stonewalling Congress by refusing to hand over documents and blocking witness testimony that House committees need to perform their constitutional duties of oversight and investigation. She says the president has abused his emergency powers in unconstitutional attempts to circumvent Congress and usurp its power of the purse.

She says, in other words, that Trump has committed impeachable offenses — but she declines to open an inquiry into whether he should be impeached. That is a difficult position to defend, including on political grounds.

The speaker is trying to use her committees to present what amounts to a made-for-TV version of the Mueller report. Trump is a master of reality television and understands its power, so he is doing everything he can to deny Pelosi the actors and the script she needs. How does it help Pelosi’s political position for her committee chairmen to spend months fighting in the courts for bits and scraps? What good does it do to hold a hearing starring Richard Nixon’s White House counsel, John Dean, when the witness you really need is Trump’s onetime White House counsel, Don McGahn?

Pelosi has said she believes that Trump is trying to bait her into impeachment. I think he’s trying to bluff her out of it. I don’t think he wants the historical stigma that would mar his presidency — or the greater power it would give Congress to compel testimony and documents.

Pelosi is famous for making a plan and sticking to it, so I fear all of this is falling on deaf ears. She and her caucus are going to start hearing from the party’s base, though. And the demands of history often overwhelm even the most carefully plotted strategies.