Lawmakers are picking their way through the massive and complicated nuclear deal with Iran in a series of hearings ahead of an expected vote in September whether to approve or disapprove of it.
The deal was reached July 14 in Vienna between Iran, the United States and five other world powers, and would basically put Iran's nuclear program on ice for 10 years. In exchange, nearly all of the international sanctions that have crippled Iran's economy and legitimacy for its Shiite Muslim theocracy would be lifted.
Under a law enacted May 22, Congress has 60 days to review the deal, though not much is at stake. The U.N. Security Council unanimously approved it Monday, making it binding under international law, and only U.S. sanctions would remain in place if lawmakers passed a resolution of disapproval over President Obama's veto.
Still, most lawmakers already don't like the agreement, and even those who do approve have serious concerns about how it will work. Here are three of the major ones: