The changing demographics of the country may give Democrats the edge in presidential elections. But Congress is another matter. The Founders designed the Senate so that small states with minority views had as equal a share in decision making as the big mommas such as New York and California.

And the nation’s population distribution and racial gerrymandering schemes under the Voting Rights Act have created a situation where Democratic voters are packed into a relatively small number of districts.

But it takes broad coalitions—or Democratic majorities that make inroads into purple and red states—to pass legislation.

The problem for Democrats is their majorities rely heavily on lawmakers who cannot toe the liberal line in all cases. Harry Reid has 55 Democrats in the Senate. But some of them—McCaskill, Nelson, Begich, Landrieu, Pryor, and others from the South and Midwest—know they would have to make an early transition into lobbying if they voted for a new assault weapons ban, or for legislation that would harm the coal industry, or, dare I say, for comprehensive immigration reform.