WASHINGTON, Nov 21 (Reuters) - The U.S. Congress is facing growing calls to find a way to stem rising budget deficits and debt following this month's warning by Moody's that political dysfunction could lead it to lower the federal government's credit rating.

There is no rocket science to the three basic choices for grappling with a national debt that has doubled in just the last decade and stands at $33.7 trillion, around 124% of GDP: raise taxes, cut spending or do a combination of the two.