article_snippet: Kerry denounces GOP letter to Iran leaders .
article_snippet: Senators grill Obama officials on Iran .
article_snippet: Obama, Iranian official slam GOP letter on deal .
article_snippet: Under presidents of both parties, such major shifts in American foreign policy as diplomatic recognition of the People's Republic of China, the resolution of the Iran hostage crisis, and the conclusion of the Vietnam War were all conducted without congressional approval," Biden said in Biden statement opposing the GOP letter.
article_snippet: In the GOP letter, Biden informed Iranian leaders that many senators will serve terms longer than Obama, so many senators would have to reckon with the Senate at some point.