But Obama supporters cautioned that, even if he did, there was nothing wrong with that if there were no payoffs.

There was "no harm in Obama's staff speaking with Blagojevich and expressing a preference for the appointment as long as they didn't offer anything in return," said Thomas Mann, a presidential scholar at the Brookings Institution.

Republican Party officials, however, were stepping up their attacks on the scandal -- perhaps a sign of things to come when the Obama regime takes over next month.

"The serious nature of the crimes listed by federal prosecutors raises questions about the interaction with Gov. Blagojevich, President-elect Obama and other high-ranking officials who will be working for the future president," said House Republican whip Eric Cantor of Virginia.

Still, while political analyst Duffy thinks the Blagojevich scandal "is pretty darn serious" for the Democrats, "I'm not sure this is serious for Obama; in fact, it's probably not serious at all."

More shoes will surely drop before this investigation is over. But the Republicans are going to keep pounding the Democrats on this one to make sure that they -- and the Senate nominee they pick -- will have little chance of retaining Obama's seat.

"The Republicans could have a chance to take this seat," Duffy said. "I think a special election would give them the chance to do that with a credible candidate."