Exactly one year after the Trump administration pulled out of the Iran nuclear deal, tensions between Washington and Tehran are escalating sharply amid confusion about what, exactly, the U.S. sees as its end goal. For Iran, uncertainty about what President Donald Trump wants to achieve and what he is prepared to do to get there presents a menu of risky choices. On Wednesday, Iran announced it was withdrawing from parts of the Joint Comprehensive Plan of Action, or JCPOA, the initially seven-nation agreement struck in 2015 curbing Iran’s nuclear program that was central to former President Barack Obama’s foreign policy. […]