Was the cause of the lowering of America's credit rating by S&P Obama's renege of FY2011 promised budget cuts?

I am old enough to remember when over half of the federal budget was just paying interest on the National debt and Japan had the world's largest economy. Today debt service is 5% of the budget and Japan's economy is not a quarter the size of the U.S. My whole geriatric life Republicans have been saying the dollar will be devalued and we will lose our bond rating. Someday they will be right, but if you are betting on your lifetime being it you are a sucker.