Whether you call it the "Potomac Primary," the "Chesapeake Primary," or the "Crab Cake Primary" (see above), last night belonged to Sen. John McCain (R-Ariz.) and Sen. Barack Obama (D-Ill.). Both candidates won their respective primaries in Maryland, Virginia, and Washington, D.C. It's eight in a row for Obama over Sen. Hillary Clinton (D-N.Y.), and most political analysts say it's mathematically impossible for Gov. Mike Huckabee to catch McCain at this point. Still, Huckabee promises to make a full sprint to the finish line. And, Clinton is looking to Ohio and Texas to re-energize her campaign after losing two top campaign staffers. The Democratic race for the nomination is still so close that many in the party worry that the whole thing will come down to the superdelegates, rather than the voters. That kind of ending would likely infuriate many Democrats, and there's concern among party big-wigs that it could alienate voters just before a presidential election. We'll talk with Ken Rudin, our Political Junkie, and with a superdelegate about his role in this election, and how he views superdelegates in general.