While Republicans settled on their presidential nominee Tuesday, Democrats put off their decision for even longer. Sen. John McCain can now hit the open road. Sens. Barack Obama and Hillary Clinton must pack for the next stop on the drag-race circuit.

McCain has seemed like the inevitable nominee since early February, but less than three months ago he was still a long shot. He earned the nomination, taking his case directly to the public and playing up his strongest attributes: service, honor and (mostly) straight talk. He also caught some breaks along the way.

New Hampshire voters gave him his first victory, and it was a crucial one. McCain had the state almost to himself in the closing weeks of 2007. The other candidates were busy trying to win Iowa, where Mike Huckabee obliged McCain by bumping off Mitt Romney. Huckabee lost traction in New Hampshire, Rudy Giuliani abandoned the state and Fred Thompson never showed up.

A calmer few months in Iraq also helped McCain. The better things seem to go there, the more formidable he will become as the Republican nominee.

For now, McCain has time to define himself anew to voters across the country while Obama and Clinton fight each other.

Clinton's victories in Ohio and Texas clarified only one thing: Thoughts of her demise were premature. This was a familiar story in New Hampshire, where late-deciding voters had given her CPR.

Yesterday, there was plenty of speculation on what might happen next and how the Clinton-Obama duel might be resolved. A few things seem clear.

One is that the convoluted process of delegate-splitting, caucuses vs. primaries and super-delegates seems likely to thwart rather than reward the voters. The long campaign has energized voters all across the country in states that had seldom seen a presidential primary that mattered. The bad news is that their votes are unlikely to give either Obama or Clinton enough delegates to be nominated.

The dead heat and the backroom deals it augurs add up to real peril for the Democratic Party. No matter how gracious the loser is, the outcome is likely to embitter half of Democratic voters. This plays into the hands of McCain, whose power to draw independent voters is well-known in New Hampshire.

The one outcome that might prevent such disillusionment would be to put Obama and Clinton on the same ticket. It is hard to see this happening.

First, one of them would have to say uncle. Both have worked too hard, spent too much and won too often to give up. Besides, being a powerful senator from New York is almost certainly more attractive to Clinton than being vice president.

Obama is young enough to hope that a vice presidential run would enhance his presidential prospects later. But the idea of serving in an unappealing job with Bill Clinton looking over your shoulder may be more than such a gifted politician can take.

Aside from McCain's winning the nomination, only one thing is certain after Tuesday's primaries: More surprises lie ahead.

At the moment, it is advantage-McCain. Nobody knows better than he does how suddenly the worm can turn.