If a Democrat (either Hillary or Bernie) wins the White House in 2016 by a large margin with Obama-like coattails, there's a slim chance the Senate could switch back to the Democrats. There is virtually no chance, given the 2010 elections and the gerrymandering of House districts that followed, that the GOP will lose control of the House of Representatives.

If the Senate flipped, a Clinton or Sanders presidency would have a chance of getting a relatively progressive Supreme Court replacement for Scalia, and maybe a freer hand in advancing foreign policy goals that require Senate ratification.

But with a Republican House, neither Clinton or Sanders would have much chance to advance any kind of legislative agenda as president. Single payer health care? Gun control? Public funding of higher ed? Not going to happen.

The best a Democrat in the White House will be able to do over the next 4 years is to be a firewall to prevent the total dismantling of the Obama legacy -- the Affordable Care Act, the opening to Cuba, the Iran nuclear agreement, executive actions on immigration.

Maybe I'm wrong about the chances of winning the House back. But if I'm not, then either a President Clinton or a President Sanders is in for a very long, very frustrating next four years. As are we all.