Secretary of State John Kerry didn't mince words when asked whether or not he would take responsibility for the letter written by the neocons favorite new Senator, Tehran Tom and signed by 47 Senate Republicans on this Sunday's Face the Nation.

John Kerry slams "unconstitutional" GOP letter to Iran:

Secretary of State John Kerry criticized Senate Republicans' recent letter to Iranian leaders, saying the missive contained not only "false information" but that it was "directly calculated to interfere."

When asked whether he would take responsibility for the letter in the multi-party negotiations with foreign leaders over Iran's nuclear program, Kerry said "not on your life."

"I'm not going to apologize for the unconstitutional, un-thought-out action by somebody who's been in the United States Senate for 60-something days," Kerry told CBS News correspondent Margaret Brennan in an interview Sunday on "Face the Nation," referring to the letter's primary author, Sen. Tom Cotton, R-Ark. "That's just inappropriate."

The country's lead diplomat said the letter was an obvious attempt to meddle in foreign affairs in an unprecedented way.

"The effect and the intent of the author was to basically say, 'Don't do this deal,'" Kerry said. "It's like--you know--giving people a grade on a test before the test is even written, let alone given. It's wrong, it's unprecedented, and I hope it hasn't made it very difficult here."

The former chair of the Senate Foreign Relations Committee decried the "calculated" attempt to "interfere" with negotiations over Iran's nuclear program.

"It specifically inserts itself directly to the leader of another country saying, 'Don't negotiate with these guys because we're going to change this,'" Kerry said.