A GOP Border Reckoning

Mitch McConnell created a Beltway stir Thursday when the press reported that the Senate GOP leader had cast doubt on a deal for border security and aid to Ukraine and Israel. Republicans said later the stories were overbaked, but Mr. McConnell is right about the choice Republicans face at a dangerous moment at home and abroad.

The Kentucky Republican was noting the reality that the deal faces political headwinds, and he is right to warn his colleagues that their window for a rare accomplishment is waning. Donald Trump is trying to torpedo...