The Second Amendment and court precedent guarantee an individual's right to bear arms, but improved and expanded background checks are needed to prevent gun violence like the shocking attack in Tucson in January, President Obama wrote in an op-ed Sunday. Writing in the Arizona Daily Star more than two months after the shooting of Rep. Gabrielle Giffords and 18 others, six of whom died, Obama said he's "willing to bet" that responsible gun owners would support laws to "keep an irresponsible, law-breaking few -- dangerous criminals and fugitives, for example -- from getting their hands on" guns. "Most gun owners...