Trump Iran Rally
Donald Trump speaks at a Tea Party rally against the international nuclear agreement with Iran outside the U.S. Capitol, Wednesday, Sept. 9, 2015. Andrew Caballero-Reynolds/AFP/Getty Images

Thousands of opponents of the Iran nuclear deal turned out Wednesday to rally in Washington against an agreement that now seems to have enough congressional support to survive. Headlining the event were high-profile conservative figures, including real estate tycoon and GOP presidential front-runner Donald Trump, former Alaska Gov. Sarah Palin and Texas Sen. Ted Cruz.

"I’ve been doing deals for a long time, I’ve been making lots of wonderful deals, great deals, that’s what I do," Trump said. "Never, ever, ever in my life have I seen any transaction so incompetently negotiated as our deal with Iran -- and I mean never."

Trump and other speakers criticized the seven-nation agreement as emboldening Iran's leadership, which he said was a regional threat. Trump also charged Iranian leaders with making contradictory and hateful statements about the U.S. "We are led by very, very stupid people. ... We cannot let it continue," Trump said, speaking of those who negotiated and support the deal.

Palin likened the lifting of sanctions to rewarding bad behavior. "The whole premise of this thing, it’s wrong," she said. "We’re negotiating with the braggadocios No. 1 state sponsor of terrorism. Obama never even clenched a fist against a wicked regime where anti-Semitism and Holocaust denial is state-sanctioned ideology."

The rally, sponsored by Tea Party Patriots and the Zionist Organization of America, follows news that President Barack Obama had secured enough support in the Senate to sustain a veto or even block a vote on a resolution to kill the agreement. Republicans in Congress have come out heavily opposed to the deal, which was negotiated among Iran, the U.S. and five other world powers. The agreement also is being fought by the Israeli government, some pro-Israel Jewish advocacy groups, evangelical Christians and others.

Organizers and speakers at the rally, held on the West Lawn of the Capitol, said they hoped to galvanize enough opposition to pressure lawmakers to rethink their votes in the coming days. “It is my hope and prayer that every one of those Senate Democrats reconsiders, that they go home and they fall to their knees and they pray tonight," said Cruz, also a GOP presidential candidate.

The deal would see crippling economic sanctions against Iran lifted in exchange for a commitment from Iran's government to abandon any nuclear arms program. Opponents have scrutinized details of the deal and have questioned Iran's willingness to comply with the terms. They have also raised concerns over the lifting of international sanctions on Iran, alleging that the deal would empower Iran.

Obama and Secretary of State John Kerry, who negotiated the agreement, have insisted the deal is based on unprecedented access to Iran's nuclear facilities – not trust – and have sought to assure skeptics that Iran will be unable to develop a nuclear weapon. Obama has billed the accord "the most consequential foreign policy debate" since the vote to enter the war in Iraq in 2003.