An aggressive President Barack Obama spoke on the ongoing debt limit negotiations at a White House Press conference late Monday morning.

“I will not sign a 30-day or 60-day or 90-day or 180 day extension,” the president said of a potential stopgap resolution to stave off default. “That is not an acceptable approach.”

Obama dug in, then, on a grand deal that would include new revenue, large spending reductions, tax code changes, and an extension of the debt limit at least until the 2012 elections, if not longer.

He pleaded with progressives in his own party to agree to put their “sacred cows” — Social Security, Medicare, and other programs — on the table to make them “sustainable” and hash out a deal, though he also said these programs are not the source of America’s deficit.

We need to “eat our peas,” the president said at one point to laughter from the press corps, in the context of both sides making tough concessions.

“I’m prepared to take on significant heat from my party to get something done,” Obama added. “I’ve bent over backwards” to get a deal.

He called Republicans who have said they will oppose raising the debt ceiling irresponsible and insisted, “They know better.”

The federal government is weeks — if not days — away from financial chaos, which would stem from the first U.S. default in history.