A lot of historic barriers have been busted through in this presidential year, and another looms: Could both running mates herald from Arkansas? Democratic and Republican insiders say it might happen. The easiest to figure out is former Gov. Mike Huckabee, the darling of conservatives, perhaps joining Republican Sen. John McCain. But now there's talk that former Gen. Wesley Clark, a backer of Sen. Hillary Clinton, is getting the once-over from Sen. Barack Obama, the likely Democratic nominee. Reason: The ex-NATO boss would give Obama some national security credentials, and he might make it easier for Clintonistas to join the Obama bandwagon.