This is not as obvious as you might think. I'll explain just by giving my own bias/answer. I'm not a Democrat. Aaaaaahhhhhhh!!!!
I happen to have never voted for a Republican, and I've never, in fact, cost a Democrat an election (my so-called conscience votes have never caused a Republican to get elected).
But that's just a coincidence.
Are you a partisan?
MORE....
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I refuse to consider myself as being in some cabal "party" to which I owe some supra-philosophical loyalty. I have my principles and that is where my political loyalties lie. They include pragmatism, surely, and the Republicans are so far afield these decades there little to no chance that I will ever be voting for a Republican President. For example, even if the individual Republican candidate seemed great somehow, like an honest man lost in the Republican party, the horde of Republicans that would come in via the wider administration hiring process would cause me to think twice.
I.e. even though I believed to a degree the "compassionate conservative" line (assuming he was poppa's boy after all, a formerly pro-choice Republican, iirc), I knew we'd get a load of Ashcroft anyway (ok, Cheney right there on the ticket was a dead giveaway, and the record in Texas was not "compassionate conservativism" but I'm trying to make a point here).
The Greens are not viable, so a vote for them would not be pragmatic. I would vote Green, but only in a safe state, a safe race, for example. I might possibly vote Green if I liked the candidate and thought they could actually win. However I'm not really on the same wavelength as many Greens in terms of policy (in terms of ideals I am, but just not the policies that will best work toward those ideals).
So my status as a Democrat is more or less just acknowledgment of this pragmatism, it is the party closest to me although not as close as I would like. I simply see where my votes have gone in the past, and I can see that working with the Democratic party is likely to be my best option in the future for the next couple decades at least.
But still I'm an independant. I won't hide any dead bodies for anyone... I'll turn on a fellow Democrat in 1/2 second if they are corrupt. I won't worry one bit if it hurts the club's party's reputation when it comes time to something dark and untoward (actually such a reaction is a defense of the party if the party is about principles, in my opinion, but this is not a universally held idea). I know many people would defend something untoward for the "greater good" of the group, with all the "good" it needs to do in the future in mind. To me that's a recipe for what's happened to the Catholic church, and many many many other organizations that have tolerated their own corruption.
Some people find my attitude disloyal. It is. I don't believe in groups of people, I believe in ideas. I will support someone that makes a mistake, this is not about purity for me, we all make them, and that's just more pragmatism and compassion for the human condition. I value honesty, and that requires tolerating knowledge of peoples faults.
But in the end I think the party system is a corruption of democracy, I believe dogma is a sin against free thought and free people. (see also Pyrrho of Ellis)
Luckily for you, you don't have to have read all that to vote in the poll.
PS: come on lurker conservatives... your vote is anonymous!