Richard M. Nixon’s opening to China more than 40 years ago was a huge Cold War gamble that he could forge a working relationship with a Communist country that had built a small arsenal of nuclear weapons and clearly had long-term ambitions for global power. For President Obama , the deal struck Tuesday morning with Iran represents a similar leap of faith, a bet that by defusing the country’s nuclear threat — even if just for a decade or so — he and his successors would have the time and space to restructure one of the United States’ deepest adversarial relationships. Mr. Obama will be long out of […]