The Democrats need four Republican senators to vote with them on the rules of the Senate impeachment trial. This could compel the calling of witnesses, and even perhaps require a final conviction vote by secret ballot.

So far, Lisa Murkowski of Alaska and Susan Collins of Maine have both declared that they expect a fair trial with the outcome not prejudged, much less with Mitch McConnell working hand in glove with the White House.

But where’s Mitt? In the past, he has been among the staunchest Republican critics of Trump’s assertions that he is above the law. Lately, he has been uncharacteristically circumspect.

If Romney can add his voice to challenge McConnell, then we only need one more Republican, who could be Lamar Alexander of Tennessee or Chuck Grassley of Iowa, both of whom have occasionally criticized Trump.

That is, assuming the world is not blown to smithereens first. Maybe Trump’s latest flirtation with World War III will give some of these worthies pause.