Philip, I am not sure many folks argued pre-macaca that Sen. Allen was an A-level candidate. For reasons unique to each presidential hopeful, all the Republicans with their "hats in the ring" strike me as B-level candidates. All have serious liabilities. If you believe that, choosing a "favorite" is a half-hearted selection.
Can he win? Probably not. This Senate race is enough of a challenge right now, and the events of the last couple months are too much of a stain to turn into a road show.
Should he win? Probably not. He doesn't have the stuff to get this far without an impeccable reputation, and doesn't show any signs of improvement.
As disturbing as this race stuff is, though, since the allegations have an element of doubt about them, Allen's gutter strategy disturbs me even more. Charging Webb with being a sexist because he opposed women in combat is cheap. And now, as John Miller mentioned at the Corner yesterday, he attacks Webb for defending the Navy during Tailhook: