Media playback is unsupported on your device Media caption Rhodes on Iran nuclear deal: 'This is not a treaty'

The White House agrees that the Republican Senators' letter to Iran creates the perception that America is dysfunctional.

The White House's Deputy National Security Advisor, Ben Rhodes, was clearly angered by the decision by 47 Republicans to send an open letter to the Iranian leadership. The letter warned that any nuclear deal reached between Iran and the so-called P5+1 group could be short lived.

Rhodes told me the letter is profoundly unhelpful and fits a pattern of Congress not working constructively with the President.

In our interview today, Mr Rhodes also insisted that any deal negotiated by the White House wouldn't need to be ratified by Congress.

Mr Rhodes joined me just after Hillary Clinton had given a press conference defending her use of private email during her time as Secretary of State. Mrs Clinton said she used private mail rather than be inconvenienced by having two email accounts. Mr Rhodes wasn't concerned about any possible security implications from Mrs Clinton's emails, he said, because any classified information would have been on a separate classified system.

He did volunteer that he and his colleagues at the White House all use two devices and two email accounts.