​Donald Trump on Iran: "They have suckered us"

Donald Trump on Iran: "They have suckered us"... 02:36

WASHINGTON -- It was quite a scene at the U.S. Capitol Wednesday, as the Senate opened debate on the Iran nuclear deal. Opponents rallied outside, including Republican presidential frontrunner Donald Trump.

Trump called both the deal and the Americans who negotiated it, "incompetent."

"We will have so much winning if I get elected, that you may get bored with winning," said Trump at the rally. "Believe me. I agree, you'll never get bored with winning. We never get bored."

GOP: Iran deal will "make military conflict m... 03:46

When I asked Trump what he'll demand in the deal that isn't already there, he told me: "You're going to have to watch."

"I don't want to say things that the other side is going to learn everything about me," Trump added. "Do you understand that? That's part of the problem. Everything is talk in this country. They talk and talk. I don't want to say ... I will tell you, that deal will be totally renegotiated or worse."

Trump said it'd be worse for Iran, not for America.

"They (Iran) have suckered us," Trump told me. "They have taken advantage of stupid people, stupid representatives, people that are incompetent, whether it's Kerry or our president."

More Senators support Iran nuclear deal 02:41

Texas Senator Ted Cruz, also running for the GOP nomination, was Trump's warmup act. Cruz said even though congressional Republicans do not have support sufficient to block the agreement, GOP leaders should postpone a vote because Congress has not seen all of the fine print.

"The president lacks the legal authority to lift sanctions until the expiration of the congressional review period because he refused to hand over the side agreements," said Cruz. "The congressional review period hasn't started yet."

New comments from Iran's supreme leader are giving new fuel to the deal's opponents. Ayatollah Ali Khamenei called the U.S. - yet again - the Great Satan and said Israel will not exist in 25 years.

Democrat Hillary Clinton repeated her support for the nuclear agreement Wednesday, but added this warning to Iran about non-compliance: "I will not hesitate to take military action if Iran attempts to create a nuclear weapon."

It will be largely up to the next president to implement terms. Already there are warning signs. The United Nations' nuclear watchdog agency said Iran has provided incomplete answers about its past pursuit of nuclear weapons.