The more obvious move is to find a Sister Souljah--after Saturday--to stiff arm. The most promising candidate is not a person, but an idea: race-based affirmative action. Obama has already made noises about shifting to a class-based, race-blind system of preferences. What if he made that explicit? Wouldn't that shock hostile white voters into taking a second look at his candidacy? He'd renew his image as trans-race leader (and healer). The howls of criticism from the conventional civil-rights establishment--they'd flood the cable shows--would provide him with an army of Souljahs to hold off. If anyone noticed Hillary in the ensuing fuss, it would be to put her on the spot--she'd be the one defending mend-it-don't-end-it civil rights orthodoxy.
I can't think of a better plan. Can you?
P.S.: Abandoning race-based preferences would certainly solve Obama's Boldness Gap, as described by Dan Gerstein.
The idea of momentum is that you generate support in subsequent primaries when you win one. Not this year. Fox News anchor Brit Hume now refers to "no-mentum." Obama won Iowa, then lost New Hampshire. John McCain won New Hampshire, then lost Michigan. And so on.