It was hard to know where the good news ended for Barack Obama after the Potomac primaries. There had been no question that Obama would dominate in DC and Maryland. But his overwhelming romp in Virginia–one of a handful of formerly “red” states that are tossups for 2008–made the best case yet that the Illinois senator just might live up to his promise of blasting the red-blue electoral map to smithereens come November.

Meanwhile, the surprising Republican results in Virginia, where Mike Huckabee gave John McCain a scare, bolstered Obama’s argument just as effectively. It wasn’t a shock that McCain fared poorly among right-wing Christians and the sort of NASCAR Republicans who have been guffawing happily over the revelation that the genial theocrat from Arkansas fried squirrel in a popcorn popper during his heck-raising college days. But the results underscored a point that defies conventional wisdom: McCain’s shakiness among the very voters–suburban independents–who are supposed to be his ace in the hole. While Obama was winning over all kinds of Virginians he was not supposed to have a prayer with, McCain was losing some of those he absolutely has to have. And losing them in a state that he has to carry to have any chance of becoming President.

Like Missouri and Colorado, both of which Obama won on Super Tuesday, Virginia can make a valid case for being the Ohio of 2008–the next ideologically mixed, demographically topsy-turvy state where Republicans will have to fight mighty hard to defend their turf. With the influx of nonnative professional types and Latino immigrants into northern Virginia in recent decades, the Old Dominion has become a thoroughly middle-American state of the twenty-first century in terms of its politics–a lively mash-up of conservative Christians, blue-state liberals, rural populists and swelling ranks of independents. It’s American politics in miniature. And that’s what makes the results–on both sides–so revealing.

Obama won pretty much every constituency he’s presumed to be weakest with: women (60 percent in rough exit polls), rural voters (narrowly), Latinos (54 percent) and folks with no college education (63 percent). He won handily among those who think Iraq matters most, who think healthcare matters most, who think the economy matters most. He took more than 60 percent of the vote among those making both less and more than $50,000. Obama narrowly carried the white vote in Virginia, building on his momentum among the notoriously stubborn Caucasian Democrats of Dixie, having won 25 percent of white votes in South Carolina (when the race was still three-way) and then bucked it up to 43 percent in Georgia on Super Tuesday. He also won the stubbornest demographic in Virginia: whites over 65. Only white women went for Hillary Clinton, and by nowhere near Obama’s eighteen-point margin among white men.

As Democrats look forward to a matchup with McCain, one set of numbers sticks out from the rest: Obama got double Clinton’s vote among white independents in Virginia, winning 66 percent. Meanwhile, in the single most stunning number of the night, McCain actually lost among independents who cast their ballots in the Republican primary. His margin of victory came not from independents but from Republicans–a terrible omen for his “electability.” Huckabee also ran close to McCain in those bastions of independent (but also, of course, megachurch) voting, the suburbs, while Obama was pulling 60 percent of suburbanites on the other side. The other prime indicators of how independents might vote in November looked equally good for Obama and lousy for McCain: while Obama won big with under-45 voters, who are the most likely to register independent, McCain lost big among the youngest voters (under 30) while taking 53 percent of the 30-to-44 age group. To add just one more bit of sour news for McCain, fewer independents voted in the Republican primary in Virginia this year: 76 percent of the voters were card-carrying GOPers, as opposed to 63 percent in 2000.

On the night when McCain vanquished his last remaining (long-shot) competitor, Republican voters made one thing bleedingly evident: they’d like nothing more than a do-over of this whole nomination business. Preferably with an entirely different cast of candidates. Meanwhile, the optimistic but fretful Democrats soldier on toward March 4, when Obama gets his chance to deliver a knockout punch in Ohio and Texas. It’s still presumptuous–as the change-monger himself likes to say–to count Clinton out. Obama will have to earn those victories, and earn them in the most valuable way–by selling himself to two vital groups of purple-state folks he hasn’t convinced yet: white economic populists in Ohio (who tend to vote a whole lot like white Southerners) and Latinos all across the Lone Star State. But a distinct pattern has already emerged: Obama runs stronger where the party has a historic chance to win back the middle, states like Iowa, Missouri, Colorado–and now Virginia.

Purple America is ready, and eager, for Obama. His popularity with young voters, independents and suburbanites could very well translate into general-election victory. As for McCain–who is being hectored to pander even more to the GOP’s right-wingnuts, which will only further alienate his former independent fans–his chances seem to boil down to one increasingly improbable headline: Hillary Clinton Wins Democratic Nomination.