A Republican campaign ad describes the "buyer's remorse" some voters feel about President Barack Obama, while another ad features a woman saying she had supported Obama because "he spoke so beautifully," but he's failed to deliver on his promises. Yet another ad woos Obama supporters with a direct but gentle prod: "It's OK to make a change." Come on in, the water's fine. That's the message from Republicans as they try to persuade voters who supported Obama in 2008. Nearly all of the $100 million Romney and his allies have spent on TV ads in general election battleground states has been aimed at a single audience.