Senate Majority Leader Harry Reid (D-Nev.) on Tuesday introduced a bill that would require background checks to be run on anyone buying explosive powder, a reaction to last week's Boston Marathon bombing. Reid introduced the bill, S. 792, for Sen. Frank Lautenberg (D-N.J.), who has been out sick for much of the year. But in a press statement, Lautenberg said the Boston bombing shows that background checks are needed for explosive materials. "It defies common sense that anyone, even a terrorist, can walk into a store in America and buy explosive powders without a background check or any questions asked,"...