It’s ironic that one of the clearest explanations for why President Donald Trump should be impeached is coming from a member of his own party. Michigan Representative Justin Amash, a devout libertarian Republican, said this week that the Mueller report describes “impeachable crimes” on the president’s part. “Some of the president’s actions were inherently corrupt,” he wrote on Twitter on Thursday. “Other actions were corrupt—and therefore impeachable—because the president took them to serve his own interests.”

Amash is the first Republican lawmaker in either chamber to publicly draw this conclusion. That speaks volumes about his colleagues, who have largely echoed the president’s up-is-down refrain that the report’s damning findings are a “total exoneration” of him. But it says more about Speaker Nancy Pelosi and other top Democrats. Their strategy of describing Trump as a lawless threat to the republic while refusing to begin impeachment proceedings against him has gone from simply untenable to openly laughable.

Anti-impeachment Democrats offer multiple reasons not to begin the process. Some have argued that the American people aren’t yet supportive enough of impeachment to justify it. Others have warned that it could energize Trump’s base and alienate moderate voters, thereby paving the road to his re-election next year. Many of them have argued that impeachment is a futile gesture while Republicans control the Senate, where a two-thirds vote would be needed to remove Trump from office. But none of these excuses are persuasive. And when placed alongside Amash’s honorable stand against his own party’s leader, they smack of political cowardice.

This approach was defensible at first. Impeachment is a weighty process that should not be undertaken lightly, so it’s understandable that Democrats wanted to show some caution before launching it. They also understandably wanted to hold off while Mueller’s investigation was ongoing, in case he uncovered evidence that would be relevant for impeachment proceedings. With Mueller’s findings now public, those arguments for prudence have lost currency.

Pelosi’s opposition is particularly galling since she’s one of the president’s most vocal critics. “The president’s behavior in terms of his obstruction of justice, the things that he is doing, it’s very clear,” she told reporters on Thursday after Trump walked out of a White House meeting. “It’s in plain sight. It cannot be denied. Ignoring subpoenas, obstruction of justice. Yes, these could be impeachable offenses.” At the same time, the speaker is working tirelessly behind the scenes to quell members of her party who want the House to take more decisive action.