Sometimes? In my view, it's always. Probably 90% of the people voting Republican have major differences on major issues with the GOP candidate running. But they vote for him anyway - because the other guy is worse. It makes no sense letting Stalin get into power because the GOP guy disagrees with you on some issues. Half a loaf is better than none. (I happen to think McCain is a great guy personally, but disagree with him on everything from amnesty and torture to the bailout).
Exactly my point. Say what you will about McCain, can any of you McCain haters honestly say that America would have been worse off on July 20, 2009 than we are today if McCain were President? Would we have a runaway Congress running amuk? Would we have a leader bowing down to Saudi kings and shaking hands with evil dictators all the while smacking Israel in the face? Would we be facing this monstrosity of a health care nightmare? Would the House have passed Cap and Tax? I think you know the answer.
You holier than thou conservatives refusing to vote for anything less than your perfect candidate may have (not necessarily did) put us in this boat. Voting has consequences but so does NOT voting and you have to accept the consequences of your choices. We are here PERHAPS because of those who stayed home.