Can Obama Buy A Second Term?

Nope:

Money certainly does matter in some campaigns — it’s just that the one place it makes the very least difference is presidential general elections. In primaries, voters with no cues from their party are searching for information and therefore especially open to persuasion. In downballot races that receive little press attention, advertising may even be able to override party loyalty, since it might be the only (other) information many voters have — especially in those races in which one candidate spends plenty and the other doesn’t.