Why would Limbaugh say something so dumb? Who thinks Congress can pass a simple statute and change the US Constitution?
An agreement between the US and Iran appears to be a treaty to me. The US Constitution says that it requires two-thirds of the Senate to ok a treaty. I expect this to be litigated. So the 33rd vote hardly gets Obama the votes he needs for this treaty.
[The President] shall have Power, by and with the Advice and Consent of the Senate, to make Treaties, provided two thirds of the Senators present concur...
It's vague. The best policy is "Go negotiate a Treaty, then we'll decide whether it's worth it or not." But the clause can be read to permit a Corker abomination of "Go negotiate a Treaty with Iran."
I strongly suspect our worthless Supreme Court would find this process Constitutional because of the vagueness of the clause. Just because it's stupid to give a Marxist/Muslim a blank check in the Treaty-making process doesn't make it unconstitutional.