Starting Line

"Once again two great armies will be coming back to Pennsylvania to fight the decisive battle."

Tony Corrado, a professor of government at Colby College, is one of the few real experts on the Democratic Party's byzantine delegate-selection process and the strategies that flow from it. When he started using Gettysburg metaphors on Wednesday morning to describe the upcoming six-week fight for Pennsylvania, I almost felt as if someone had hit a reset button and the campaign were starting over.

Most analysts expected Hillary Rodham Clinton to win Ohio or Texas, possibly both, plus Rhode Island on Tuesday, but predicted that her victory margins would be too narrow to gain her much ground on Barack Obama. We all know the mantra by now: Under the Democratic proportional representation system, it's hard to build a lead and even harder to overtake one. Heading into this week, Obama didn't have a big lead, but it was a lead -- and he had won 11 contests in a row. Clinton's chances of overtaking him seemed infinitesimal.

Clinton, however, didn't just capture both of Tuesday's big states; she won Ohio by a wide margin. Her victory there was so dramatic, 54 percent to 44 percent, that it seems to have changed the narrative of this contest. The momentum has suddenly shifted again.

So where do things stand? Using NBC News's delegate count as a yardstick, immediately before Tuesday's voting, Obama had a 157-delegate lead, 1,194 to 1,037. Afterward, he was ahead by 132 delegates, 1,307 to 1,175. Various other news organizations put Obama's lead as low as 82 delegates. So, Obama has somewhere between 65 percent and 77 percent of the delegates needed for nomination. Clinton has between 58 percent and 72 percent.

But as a practical matter, the wave of up to 50 superdelegates that many observers had expected to flow from Clinton to Obama or to "undecided" after March 4 isn't likely to materialize. Likewise, the anticipated level of clamor for Clinton to get out of the race isn't being heard. She couldn't drop out now even if she wanted to. Obama had his toughest news conference yet on Tuesday, and he got roughed up in a way that Clinton would find familiar. Then the election results rolled in.

Obama's momentum has halted, and the battle lines have shifted. Many superdelegates will now want to keep their powder dry until after Pennsylvania votes on April 22.

For all of the hullabaloo about superdelegates, the nearly 800 elected and party officials who are automatic delegates to the national convention were never likely to overturn the clear choice of the party's rank and file. But breaking what could turn out to be nearly a tie -- a very, very close race in which there is no clear leader -- that's quite different.

The Keystone State won't necessarily vote the way the Buckeye State did, but it just might -- meaning that a race that seemed virtually over just a few days ago isn't so over anymore. Now that Democrats know they're picking who will go up against John McCain, Clinton's argument that she has more experience and a better grasp of foreign policy than does Obama, who began his presidential campaign just two years out of the Illinois state Senate, seems to be resonating with more voters. And Corrado argues that McCain's acknowledgment that he doesn't know a whole lot about the economy -- at a time when the country is skating near a recession -- may have also changed the narrative of the campaign in Clinton's favor.

Clinton spun her wheels for a long time in terms of message, but she has finally found some traction just as Obama's credibility is being seriously challenged for the first time because of remarks that one of his senior economic advisers made to a Canadian official about the North American Free Trade Agreement.

So it is on to Pennsylvania. What about the disputed Florida and Michigan delegations? Clearly, delegates selected as a result of primaries that violated national party rules will not be seated. Some observers expect Michigan and Florida to hold Democratic caucuses, perhaps in May. Those states are so large that do-over, mulligan contests could make the difference if the Pennsylvania balloting doesn't decide the nomination first. Wow.