UPDATE: Obama takes D.C.
UPDATE II: And Obama scores the triumvirate.
UPDATE III (Adam): Barack didn't just win, he overwhelmingly won all three "Potomac Primaries" (read: not caucuses) - D.C., Maryland, and Virginia. According to CNN exit polls, Obama won 90% of the black vote, but also 48% of the (southern) white vote (somewhere, George Allen is crying) in VA. Astonishingly, he also won women by nearly 60% and Latinos by 55% in both VA and MD. Those are some serious breakthroughs, and explains why it wasn't even close (Obama could be very competitive in VA in the general). Obama has now won the last 8 contests, and will likely make that 10 when Wisconsin and Hawaii vote next Tuesday. He now leads Clinton in the overall delegate count.
From Chuck Todd - "No matter how one slices the election results from last night, there's no denying that Obama is the statistical front-runner. He's got a 100-plus pledged delegate lead and even has the lead if you factor in superdelegates... What does this mean? For Clinton to overtake Obama for the pledged delegate lead -- which we think is the single most important statistic for the superdelegates to decide their vote -- she'll have to win 55% of the remaining delegates. Assuming next week goes Obama's way in Wisconsin and Hawaii, that percentage rises to 57%. Toss in likely Obama victories in Vermont, Wyoming, Mississippi, Oregon, Montana, and South Dakota, then Clinton's percentage need tops 60% of the remaining delegates available. And this is simply for her to regain the pledged delegate lead…"
That's an astonishingly high bar for her. An Obama win in either Texas (probably the biggest battle of the two we have left) or Ohio would put the delegate lead out of reach for her entirely (the way Texas allocates delegates already favors Obama anyway, even if he loses). But since neither of them can reach the requisite delegate count to get the nomination at this point even if they won all the rest of the states, that still technically leaves it up to super delegates and, possibly, the FL and MI delegations (let's hope it doesn't come to that because there's no great options for us there). But if Obama gets that far ahead, the super delegates will quickly unite behind him (they can't deny the person who has won the most pledged delegates, the most states, more of the popular vote, beats John McCain in national polls, and has started to take the lead nationally among Democrats). The party establishment would almost certainly ask Clinton to step down then and we'll avoid a convention battle.
However, it is still very possible Clinton could win Ohio, Texas, and (later) Pennsylvania. She's had a bad spate of media coverage with all the people leaving her campaign, former staff endorsing Obama, etc. But it is a real possiblity that Edwards could endorse her and that will help. More importantly, Clinton being down seems to have galvanized her supporters in the past, but I while New Hampshire was still early on, Democrats may be looking for a firm nominee now that the Republicans have one. I think those consecutive polls showing Obama beating McCain really helped because people are now looking most at who has the best chance of winning.
UPDATE IV: Nat-Wu on this TIME piece: "The results also show the ways in which Obama is exerting a huge gravitational pull on both races. Obama is drawing so many moderates and independents to the Democratic race from what would normally be the ranks of the Republican electorate that 1) he's rolling up large margins and stitching together a broader coalition, and 2) he's making the Republican electorate comparatively smaller, and more conservative. Exit polls noted that one half of Virginia's voters were evangelicals; one third were self-described as "very conservative" while only a quarter were independents. As a result, Mike Huckabee was able to take 41% of the state's Republican vote."