When it came to the war in Georgia, McCain managed to make a position he shares with Obama seem even crazier than it already is, because his generally reckless and impulsive style has led him in the past to stake out provocative anti-Russian views that gave his support for Saakashvili the air of fanaticism. Obama hedged his initial position and then came around to the Washington consensus view, which McCain backers see as dithering and sane people find slightly more reassuring, but in the end he tends to come around to very bad, horrible positions, just as he did on FISA legislation. So, given the alternatives between someone who instinctively adopts a terrible position and someone who grudgingly makes his way to the same position, we are still provided with a pretty striking contrast between the candidates.
McCain will have us on tenterhooks on a daily basis wondering whether he will call for impeaching the Supreme Court or bombing Uruguay and he will denounce anyone who questions his proposal as a selfish and corrupt villain, and while Obama might adopt equally awful views he will do so more slowly and allow the rest of us time to organize opposition and rational counterarguments that might actually prevail.
http://www.amconmag.com/larison/2008/09/25/maybe-a-nickels-worth-of-difference/