The White House aggressively struck back Friday after Sen. Charles E. Schumer announced his opposition to President Obama’s Iran nuclear deal, suggesting the New York Democrat could lose support to become party leader in the Senate in 2016 if he helps block the accord. The response was the latest example of the president’s take-no-prisoners approach to ensuring the survival of a pact he views as a legacy-defining achievement that could help remake the security situation in the turbulent Middle East. The White House and its allies expressed confidence that Schumer’s opposition would not be enough to derail the Iran deal. Senate Democratic aides said 15 members of the caucus have expressed support, and Schumer is the only one to publicly oppose it. But both sides acknowledged that the debate is now […]