Moody’s today reassured investors that the United States government won’t lose its AAA credit rating…yet. Last week Standard & Poor warned that it might soon drop Britain’s debt rating, sparking panic that other governments could follow. A Moody’s VP said the US’ rating is the highest possible and safe for now—but warned that massive debt, plus Social Security and Medicare costs, could put “negative pressure” on it in the future. (More credit rating stories.)