I do not vote according to Party line. There are many positions that I disagree with the Democratic Party on, SAME for the Republican Party. I would never allow an organization like a Union to dictate to me who to vote for. They may "recommend" a candidate based on what they perceive as being best for the improvement of life for it's members.
However, as an American citizen under this Republic (for now at least) you are Free to vote for whomever you wish.
There were many things about McCain that I liked decades ago. Not now...nor am I fond of Bill Clinton as I once was. John McCain's well known angry behavior problem is dangerous in a world leader. His penchant for lying. His over exaggeration regarding his military history (I am former Navy Nuclear Submarines...THE most elite force in the Navy, I don't wear it like I am superior to the rest of the men and women in America as he does). His age, his questionable decision making lack of skills, such as Palin and their recent race pandering politicking. I believe John McCain is a danger to the stability and continuity of the United States as President.
I will vote for Mr. Obama, he has presented a message and persona of leadership that our nation is desperately in need of. His intellect and pulse on the Street of America (across may divides) sets him a part from most politicans. He is by no means with out his faults, but when was the last time we had one of those. Moreover, should he not be able to serve out his term, I am very comfortable with the continuation of Senator Biden as President...just as I was Lyndon Johnson (who was one of the greatest in history in my opinion)
Mr. Obama