Clinton is also navigating delicate ties with Israel and the American Jewish community, an influential group of voters and donors. Israeli Prime Minister Benjamin Netanyahu, a fierce critic of the Obama administration's outreach to Iran, described the framework deal as a threat to "the very survival" of his nation. When Obama was getting credit for the clandestine negotiations, Clinton's aides made sure reporters knew that the approach had started during her tenure at the State Department. Brian Katulis, a senior fellow at the left-leaning Center for American Progress who focuses on national security policy in the Middle East and South Asia, said if a full deal is reached by the summer, Clinton would be "part of something historic" because of her initial role. With public polling showing a majority of Americans favor a diplomatic resolution to Iran's nuclear ambitions, Katulis said, "any effort by Republicans to criticize Clinton's support for diplomacy might ultimately push them to the margins of today's national security debate and away from the center." After dozens of Republican senators sent a letter to Iran's leaders warning that Congress could upend a deal, Clinton said the lawmakers were "out of step with the best traditions of American leadership."