“When President Obama began making the case for a deal with Iran that would delay its ability to assemble an atomic weapon, his first argument was that a nuclear-armed Iran would set off a ‘free-for-all’ of proliferation in the Arab world. ‘It is almost certain that other players in the region would feel it necessary to get their own nuclear weapons,’ he said in 2012.”
Source: Saudi Arabia Promises to Match Iran in Nuclear Capability – NYTimes.com