WASHINGTON -- Nearly a year after the Senate failed to expand gun background checks as a response to the massacre in Newtown, Connecticut, it looked as though the National Rifle Association had claimed another scalp. Dr. Vivek Murthy, President Barack Obama's pick for surgeon general, had been approved by a Senate committee in late February, only to be engulfed in controversy when a 2012 tweet was uncovered in which he declared guns a "health-care" issue. Several Senate Democrats facing tough re-election battles in 2014 balked at their president's nominee.