Why nominating Clinton would be a Very Bad Thing

Electability. There's a damn good chance she could lose to McCain.

• She has the highest negative approval numbers of any candidate in polling history. (I don't think she deserves that hatred, but there it is.) No presidential candidate with her negatives has ever won.

• She would turn out the Republicans in frantic droves. Obama would turn out Democrats in droves; social-conservative 'pubs who are tepid about McCain would just stay home.

• If there's another terrorist attack, McCain will be even more likely to win. Obama would be our only hope. I won't list all the things that make Obama attractive in that scenario. They might be enough. The perception of Hillary as a waffler would destroy any chance of a win.

Governing. Deserved or not, Hillary is an incredibly divisive figure. She'd find it difficult or impossible to forge bipartisan consensus, even though some semi-sane 'pubs (notably McCain) have worked with her in the Senate. The popular pressure on Republican legislators not to work with her would be intense. (Not even considering their own inclinations.) Short story, try as she might, she couldn't govern well.

Obama. We—America, and the whole world—desperately need Obama as president. His message, his face, and his name would do more to repair America's place in the world, and heal the world overall, than any other conceivable thing.