At some point, Republicans are going to have to admit that the king is mad. Trump’s latest gambit, his contention that House Intelligence Committee Chair Adam Schiff should be arrested for treason—for accurately summarizing the whistleblower complaint—shows just how unhinged Trump has become.

Many commentators had argued that a formal impeachment investigation would be risky. Their argument was that impeachment would divert attention from pocketbook issues, the Democrats’ strong suit, on whose basis Democrats made big gains in the 2018 midterms; that impeachment on balance would help Republicans politically; and that Democrats would be going against public opinion.

These contentions were wrong. A majority of Americans now favor a full impeachment investigation. Given the new allegations, defending Trump will damage Republican senators, especially in swing states where 11 incumbent Republican senators will be vulnerable in 2020.

Win or lose, impeachment will be over by next spring or even earlier, and Democrats and Republicans can go back to debating issues that play to Democratic strengths, and with a seriously wounded incumbent president.

The risk of impeachment was never political. But it was a risk nonetheless, because impeachment is clearly making a crazy man even crazier. Lord only knows what Trump will do next—or what it will take for more than a handful of Republican legislators to conclude that he has to go.