[USATODAY] A wary Congress voted Wednesday to authorize President Obama's mission to arm and train Syrian rebel forces as part of the administration's effort to dismantle the threat posed by the Islamic State militant group.The bipartisan 273-156 vote came after days of debate in which lawmakers across the political spectrum expressed doubts about the scope and merits of the mission but conceded that the potential threat to the U.S. is too great to ignore.