There’s room for doubt. Barring the most sensational disclosures, impeachment in the House will never lead to conviction, unless at least 20 Republicans join Democrats to reach the required two-thirds majority in the Senate. That could still help Democrats, if a majority of Americans conclude that Trump is clearly guilty of serious crimes and that impeachment is the only viable recourse.

But that doesn’t seem to be happening — at least not yet. As of Wednesday, a Quinnipiac poll found that 57 percent of Americans oppose impeachment, against 37 percent who support it. That means that a significant bloc of voters who otherwise disapprove of Trump nonetheless oppose impeaching him. If this is the risk Pelosi wants to take with swing voters, Republicans will be happy to let her take it.

Those numbers could always change, depending on what we learn about the facts, as well as on how we understand the law. In a remarkable column in Politico Magazine, the former federal prosecutor Renato Mariotti makes the case that even if Trump had offered an explicit quid pro quo to the Ukrainian president, it would not violate federal bribery statutes or any other existing criminal statute.

Mariotti nonetheless argues that what Trump is alleged to have done is so bad that it merits impeachment as a breach “of the president’s duty to not use the powers of the presidency to benefit himself,” in this case politically. Come again? That’s what presidents do all the time, only Trump does it more flagrantly.

A stronger argument is that no president should use the power of his office to try to dig up dirt on a political opponent — as, for instance, Lyndon Johnson did, abusively and persistently, to Barry Goldwater in 1964. That’s absolutely true.

But disgraceful behavior is not the same thing as criminal behavior. Democrats may now find themselves in the curious position of trying to convince the country that Trump should be booted from the office to which he was lawfully elected for behavior that, whatever else might be said about it, was not unlawful. That will be a tough sell.

No wonder Trump seems to be spoiling for this fight. With an eye on Bill Clinton’s presidency, he may even relish a lengthy impeachment battle that uncovers no crime while showing that congressional Democrats are more intent on pursuing a vendetta against a president than helping the people they’re elected to serve.

I write all this as someone who thinks that Trump disgraces the office of the presidency every day he occupies it, and did so again with his call to the Ukrainian president. The best way to end this administration — and the only realistic way — is for him to be convincingly turned out by a vote of the American people next year. Impeachment risks putting that goal much further out of reach.

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