For all of my opposition to Donald Trump, I have long been skeptical of the political wisdom or evidentiary basis of efforts to impeach him.

My reasons: First, being a terrible president and a wretched person are not impeachable offenses. Second, Robert Mueller's investigation has so far produced evidence that can be interpreted as obstruction of justice but not as clear proof. Third, impeachment in the House would be unlikely to translate into conviction in the Senate, even if Democrats win both chambers in the fall. Fourth, impeachment without conviction could strengthen Trump politically, much as it did for Bill Clinton after his own 1998 impeachment.

And, like it or not, Trump remains popular with tens of millions of Americans. To overturn the results of an election for anything less than unambiguous evidence of criminal behavior is a danger to democracy itself.

At least that was my view until this week. Michael Cohen's guilty plea changes this. The Constitution's standard for impeachment is "Treason, Bribery, or other high Crimes and Misdemeanors." The standard is now met.

Trump's longtime fixer acknowledged in court Tuesday that he had violated campaign finance laws by paying hush money to two women "in coordination with and at the direction of a candidate for federal office." That means Trump. That means that, as a candidate, Trump is credibly alleged to have purposefully conspired with Cohen to commit criminal acts. That means the duo did so "for purposes of influencing [an] election for Federal office," which is the legal definition of a campaign contribution.

It also means that, as president, Trump allegedly sought to conceal the arrangement by failing to note in his 2017 financial disclosure forms his reimbursements to Cohen. The president most likely continues to lie to the American people about the nature and purpose of those payments.

The Trumpian rebuttal to these charges is that Cohen is a sleazy lawyer and proven liar. And that the most prominent attempt to prosecute a political figure for violating campaign-finance laws — involving former Democratic senator and 2004 vice-presidential candidate John Edwards — failed in court. And that campaign-finance violations don't rise to the level of impeachable offenses, anyway.

But if Cohen's lies as Trump's lawyer are one thing, lying under oath to a federal judge is quite another. Cohen's sentencing isn't until December, when he's expected to be sent to prison for up to five years. If he's being untruthful, that leaves plenty of time for any deceits to come to light. Ask yourself: Does he look like a guy eager to have his sentence doubled?

As for the Edwards standard, the case failed because prosecutors could not prove that the former North Carolina senator received campaign donations from benefactors to influence an election, rather than simply cover up an embarrassing affair. In Trump's case, there is little doubt about the purpose of the payment to Stormy Daniels: To prevent disclosure of their alleged liaison, less than a month before the election and barely two weeks after the "Access Hollywood" tape came to light.

To suggest that this doesn't amount to a felonious act also doesn't pass the smell test. The president is now, in effect, an unindicted co-conspirator on charges already prosecuted by the government as a criminal matter against Cohen. Why should a lighter standard apply to Trump, since he's the one at whose direction Cohen claims to have carried out the payments?

That question should especially engage those conservatives who demanded Clinton's impeachment (as I did). Take South Carolina's Lindsey Graham, one of the House managers overseeing the case against the 42nd president.

"Twenty-five years ago," he said that December, "a Democratic-controlled judiciary committee, with a minority of Republicans, reported articles of impeachment against Richard Nixon. Why? Nixon cheated — he cheated the electoral system — — by concealing efforts of a political break-in, and his people thought the other side deserved to be cheated. They thought his enemies deserved to be mistreated. Ladies and gentlemen, they were wrong."

He continued: "Today, Republicans, with a small handful of Democrats, will vote to impeach President Clinton. Why? Because we believe he committed crimes resulting in cheating our legal system. We believe he lied under oath numerous times, that he tampered with evidence, that he conspired to present false testimony to a court of law. We believe he assaulted our legal system in every way. Let it be said that any president who cheats our institutions shall be impeached."

The emphases here are mine. To conservatives reading this column, ask yourselves the following questions:

If breaking the law (by lying under oath) to conceal an affair was impeachable, why is breaking the law (by violating campaign-finance laws) to conceal an affair not impeachable?

If "cheating the electoral system" (by means of a burglary) was impeachable, why is cheating the electoral system (by means of illicit hush money) not impeachable?

If cheating "our institutions" (by means of an "assault" in "every way" on the legal system) is impeachable, why is cheating those institutions (by means of nonstop presidential mendacity and relentless attacks on the Justice Department and the FBI) not impeachable?

Pragmatists will rejoin that there's no sense in advocating impeachment when the GOP controls Congress. I'm sorry that so many congressional Republicans have lost their sense of moral principle and institutional self-respect, but that's a reason to seek Democratic victories in the fall. The Constitution matters more than a tax cut. What the Constitution demands is the impeachment and removal from office of this lawless president.