The Us Congress begins its review of a nuclear agreement reached between world powers and Iran, the Joint Comprehensive Plan of Action, on Thursday. Hearings start in the Senate Foreign Relations Committee, where three principals of the Obama administration tasked with crafting the deal – US Secretary of State John Kerry, Energy Secretary Ernest Moniz and Treasury Secretary Jack Lew – plan to testify. They will also appear before the House Foreign Affairs Committee next week. Their review begins amid a multi-million dollar effort, from both opponents and advocates of the agreement, to influence the outcome of the congressional vote. The lawmakers now have the opportunity to vote to approve or disapprove of the deal within 56 days. For a vote of disapproval to have any practical impact on the JCPOA, more than twothirds of both houses of the US legislature will have to vote against the agreement. That coalition of Democrats and Republicans would be necessary to overcome a veto from President Barack Obama, who has vowed to protect his signature foreign policy achievement. The chairmen of the Senate and House committees – both Republicans – have voiced strong disapproval of the deal. And their Democratic ranking members expressed disappointment as the Obama administration submitted the agreement to the United Nations Security Council for adoption before Congress had begun the review process. Republican lawmakers are universally opposed to the deal in its current form; Democrats have remained largely silent on how they plan to vote. Some have expressed concerns, and fewer have issued endorsements; the majority say they plan on carefully reviewing the agreement over the coming weeks. The White House, alongside the governments of Britain, France, Russia, China and Germany, assert that the JCPOA will verifiably prevent Iran from acquiring nuclear weapons. Critics of the deal say it emboldens a violent Islamic Republic; fails to secure a sound inspections regime into Iran's nuclear work; and legitimizes the Iranian government as a nuclear-threshold state. Israel's ambassador to the US, Ron Dermer, held meetings on Capitol Hill on Wednesday with Republican lawmakers. Along with the entirety of Israel's political leadership, Dermer has been vocal in his criticism of the agreement and has publicly declared his intention to kill it using all tools at his disposal. Obama has been engaging his critics by questioning their track records on foreign affairs, their smarts and their motives. Earlier in the week, he said the Iran deal his team brokered was the "smarter" approach to solving the decades-long conflict, and suggested that its critics were the same people whose polices led to the second Iraq War. "I f you had brought [former US vice president] Dick Cheney to the negotiations, everything would be fine ," Obama quipped on Tuesday night, appearing on The Daily Show with John Stewart for the seventh time. Stewart seemed to question the president's general approach to Iran in the interview, asking him, "Whose side are we on?" "This is an adversary," Obama said. "They are anti-American, anti-Semitic, they sponsor terrorist organizations like Hezbollah." "Sounds like a good partner for peace," Stewart interjected. The president responded that one did not need to make peace with friends. Also on Wednesday, the House of Representatives' Financial Services Committee's Task Force on Terrorism Financing held a hearing related to the nuclear deal. One expert, Mark Dubowitz of the Foundation for Defense of Democracies, said the agreement is set to cancel certain sanctions on Iran that were intended to target its overall behavior. Sanctions were put on entities such as the Central Bank of Iran for conduct-based activities not limited to nuclear activities but also including money laundering and terrorism, Dubowitz said. "The JCPOA requires the lifting of financial sanctions – including the SWIFT [Society for Worldwide Interbank Financial Telecommunication] sanctions – prior to a demonstrable change in Iran's illicit conduct. "The big winner from the unraveling of European and American sanctions," Dubowitz continued, "will be the IRGC [Iranian Revolutionary Guard Corps]." Several major American Jewish organizations have called on Congress to reject the deal in a binding manner. The American Israel Public Affairs Committee and the Orthodox Union are campaigning against it, while the Anti-Defamation League and the American Jewish Committee are calling on Congress to demand answers to several unanswered questions surrounding the watershed agreement.