WASHINGTON — Senator Jeff Flake of Arizona was in an empty hallway in the Capitol on Tuesday when he bumped into Gabrielle Giffords, the former Democratic member of Congress from his home state who was critically wounded in a mass shooting. Both froze in anticipation of the painful minute about to unfold. Ms. Giffords, who had been fiercely promoting a background check bill for gun buyers, knew that Mr. Flake, a Republican and an old friend, had announced on his... (GunPolicy.org)