If he was to hand out grades, and he is, Mitt Romney gives President Barack Obama an 'F' for the last two years of his presidency.

It's failed, the former Massachusetts governor said of Obama's administration in a taped interview that aired Tuesday on NBC's Today.

He's been one of the most ineffective presidents at the job at hand that I've ever seen, Romney said. The number one issue he faced walking in the door was an economy in fast decline. He didn't cause it, but he made things worse.

Romney, who is slated to formally announce his campaign on Thursday, said he's running because I believe I can get our economy going again.

And he has no qualms admitting that he believes he will win.

 I do give myself better than 50/50 odds, but it's up to the American people. I'll tell them what I believe and if that works, great, he said.

Romney is the assumed frontrunner in the Republican field, topping most polls among the GOP candidates for the party's presidential nomination next year.