Investors are cautiously eyeing the markets today. It's the first day of trading since Standard and Poors downgraded America's credit to double-A-plus... for the first time ever. The market's reaction today is anybody's guess:

"This is kind of unchartered territory."

The head of S&P's ratings committee said Sunday if the U.S. doesn't get its fiscal house in order, it could be downgraded AGAIN within 6 months.

John Chambers says, "The outlook includes at least a 1 in 3 chance of a downgrade over that period."

"The good news about the downgrade, if you can see any good news in it, is that it will focus the mind of policy makers to deal with its long-term problems."

But lawmakers are pointing fingers. They traded barbs on the Sunday talk shows.

This president has failed to lead and in any other private sector enterprise he would be fired."

Before the downgrade, the Dow took a huge hit - losing 500 points last Thursday - in part over debt concerns in Europe. The European Central Bank now says it will implement a bond-purchasing program to prop-up Italy and Spain's shaky economies. Treasury Secretary Tim Geithner talked with G-7 leaders Sunday night - all pledging to cooperate. He also informed President Obama he'll stay on in his post through the 2012 election.