They wouldn't have to take anything back to be able to reduce the cost of the program. They could just adjust the tax rate on Social Security income, or adjust the old-age exemption, or any number of other things without explicitly touching the SS benefit.

I chuckle to myself whenever Bush talks about making his tax cuts "permanent" or others saying that SS is a "solemn agreement with the American people" or whatever. Congress isn't going to give up its power to tinker with tax rates and the rules no matter how "permanent" they claim these things are.

FWIW.

Cheers,
Scott.