President Barack Obama on Tuesday crossed a key threshold in building support for the Iran nuclear deal , winning the backing of enough Senate Democrats that he could avoid having to use a veto to advance the accord. The new support, of 42 senators, means a shift in focus in the debate over the agreement, which was reached in Vienna in July. What had been a struggle to win over undecided lawmakers turned Tuesday into wrangling over procedure. Senate Majority Leader Mitch McConnell (R., Ky.) had been planning a formal floor debate over the Iran deal. But Senate Minority Leader Harry Reid (D., Nev.) now has enough support to block the legislation—technically, a resolution disapproving the deal—on procedural grounds, and he worked Tuesday to keep Democrats in line behind the strategy. Such a move would […]