I mentioned it in passing that Obama’s greatest challenge would be to hold his disparate coalition together long enough to win. As the campaign wears on, he’ll be forced into more concrete positions that will almost certainly alienate a portion of his current base.

That seems to be what’s going on right now with FISA and the faith outreach.

Tacking to the center would seem the safe route for any politician, but in Obama’s case, it may merely be one of two exceptionally risky routes to the Presidency. He’s inspired more excitement than any politician in a generation and he’s ridden the wave of that enthusiasm here to the cusp of victory. Now, however, he faces the excruciating dilemma of deciding which group of supporters is the largest slice of his pie.

The problem is simple - if he chooses to move to the center, he’ll alienate his supporters on the left. If he keeps to the left, he’ll hand McCain some easy pickings in the right-of-center.  Right now, he’s going the center path and it isn’t difficult to see why; the left is faced with a horrible choice - A liberal politician who’s pandering to the center, or a conservative politician pandering to the extreme right. It’s a no-brainer what their choice should be. The Obama campaign will do well to keep playing up the “close race” idea to keep these heartbroken idealists on board.

Still, it’s a risk. The time of reckoning is here for Obama - he’s now navigating out of the relatively secure niche he occupied during the primaries and trying to keep his primary coalition together while bringing in the votes he needs to win the general. Some pain is to be expected but just how his move to the center will effect his candidacy will remain a question the next month or so. That’s about when we can expect the signs of his new coalition to emerge and so find out if he’s gained or lost out in the realignment game.

Politics is about compromise. The more politically active you are, the more likely you are to be disappointed because the more active you are, the closer you hold your positions to you heart and the more convinced you are at the righteousness of your cause. The question for Obama now is whether his titanic coalition can survive contact with that harsh reality. By moving to the center, he’s once again forsaking the security of the familiar and embracing the terrifying, exhilarating uncertainty of hope.