McCaskill said she believes that if federal spending is cut too rapidly as Congress continues to wrestle down the deficit, it could send the American economy into a tailspin. 

"We're walking a tightrope here," she warned. "If we turn off the lights in terms of federal spending, we will drop off the cliff.”

The overall debt-limit agreement will cut the federal deficit by nearly $1 trillion over 10 years while raising the debt ceiling by at least $2.1 trillion through 2012.

Congress cleared that deal last Tuesday, just hours before the U.S. was projected to begin defaulting on its financial obligations.