McCain Trying to Blow the Comeback?

What in the world is John McCain thinking? He appears to be closing, people are questioning Obama's socialist economic policies and radical connections, so McCain comes out with... this ad that has Obama praising McCain-Lieberman's global warming plan?

Is McCain trying to "go positive" in the final days rather than pointing out Obama's true and very damaging views? If so, he might as well tell his supporters to vote Obama.