Already, while Romney pauses to refill his coffers, the super PAC Restore Our Future has spent more than $4 million on television advertising to introduce the Republican to the voters.

Romney had no public events Saturday after spending much of the week campaigning in Virginia and Pennsylvania.

A campaign spokeswoman, Andrea Saul, responding to Obama's speech in Ohio, said, "While President Obama all but ignored his record over 3 1/2 years in office, the American people won't. This November, they will hold him accountable for his broken promises and ineffective leadership."

With his rhetoric, Obama belittled Romney and signaled he intends to campaign both against his challenger and the congressional Republicans who have opposed most of his signature legislation overwhelmingly, if not unanimously.

After a spirited campaign for the Republican nomination, Obama said the GOP leadership found a nominee — in Virginia he called Romney their champion — "who has promised to rubber stamp" their agenda if he gets a chance.