Facing heightened pressure to revive his presidential bid, Rick Santorum was forced to explain another apparent misstep as he courted Louisiana voters Friday, the eve of a critical contest in a Republican nomination battle that increasingly favors Mitt Romney. Santorum said he would support the eventual GOP nominee - if it isn't him - despite what he insists are similarities between front-runner Romney and President Barack Obama that make them indistinguishable on some issues. He caused an intraparty uproar earlier in the week after suggesting he'd prefer a second term for Obama over a Romney presidency. "I've said repeatedly and...