Washington, D.C.,and surroundings vote today (Mark Shields has called them theCrab Cake Primaries; here in tribute to Sponge Bob is a slightly altered version).And here is E.J. Dionne on what's up for the two Democratic campaigns. He is on the mark, as usual,for the challenges eachfaces; and a little alarming on what the Democrats face when one of them wins--orfalls in exhaustion.http://www.washingtonpost.com/wp-dyn/content/article/2008/02/11/AR2008021102272.html