Kevin McCarthy is far and away the weakest congressional leader, in either party or house of Congress, in living memory. Indeed, you have to go deep into American history to find anyone comparable. And if you go too far back you get to periods when the role of House and Senate leaders were just too different to make any comparisons. So with this fact in hand, I’ve heard a number of people ask just how it is he manages to remain leader. But this question mistakes the structure of the current Republican congressional party, especially in the House. McCarthy is leader precisely because he is as weak as he is. It’s a feature, not a bug.