President Obama speaks in April after the Senate rejected a bill that would expand background checks on guns. The White House is seeking to clarify rules that bar firearm possession due to mental health problems. Manuel Balce Ceneta/AP hide caption

itoggle caption Manuel Balce Ceneta/AP

Sen. Kelly Ayotte, R-N.H., has drawn the focus of gun control proponents for voting against a bid to expand criminal background checks for gun buyers. J. Scott Applewhite/AP hide caption

itoggle caption J. Scott Applewhite/AP

Firearms for sale at a gun show in Annapolis, Md., on April 14. Andrew Harnik /The Washington Times /Landov hide caption

itoggle caption Andrew Harnik /The Washington Times /Landov