Presidents’ Day Weekend is a good time to think about the sorry state of Congress.

That’s true in part because the whole notion of Presidents’ Day sheds a little light on our distorted understanding of the character of our constitutional system. Strictly speaking, there is no such thing as Presidents’ Day. By law, the third Monday in February is a federal holiday called “Washington’s Birthday.” We have gradually and informally turned it into a broader celebration of our government’s chief executive as we have turned almost everything else about our politics into such a celebration of the second branch. This is …