ON A SHELF not far from where I am writing these words sit a half a dozen or so books disparaging Congress and complaining about the congressional role in the constitutional separation of powers. These books date mostly from the late 1940s and the early 1960s, and typically their authors are liberal Democrats. In those years, Congress was unresponsive to liberal Democrats and, naturally enough, aggrieved members of that articulate tribe sought solutions in structural reform.