President Obama and his national security team worked behind the scenes Sunday to try to shore up support within the Arab world for the military mission in Libya, with top White House aides reaching out to officials of the Arab League to insist the bombing does not exceed the scope of a U.N. mandate, according to senior administration officials. The senior officials described the Obama team's phone calls as making clear to the Arab League that bombing Libyan leader Moammar Gadhafi's air defenses falls within the U.N. Security Council resolution's scope of imposing a no-fly zone and taking "all necessary...