Barack Obama and his supporters are exuberant after their victories this last weekend in the Washington and Nebraska precinct caucuses, in the Louisiana primary and the Maine municipal caucus. But they would do well to remember that since the mid-1970s the Democratic National Committee has spent countless hours plowing firebreaks between expressions of the popular will in such caucus and primary votes and the ultimate selection of the nominee.

There was another powerful challenge in 1984, from Jesse Jackson...Jackson ran into that wall in 1988...