I don't know. If I was the run of the mill commie/socialist, I'd be pretty peeved that my experienced flag carrier, Hillary!, (who had been in the front-lines to tear down Nixon, had tried to Nationalize Health care ... all the sort of things that make me go tingly...), was dumped for some Zero who had done nothing but had been born with a slightly darker shade of skin than Hillary! -- I might be a bit miffed to the point that I wouldn't vote for the anointed one during the General Election.
And being the run of the mill commie/socialist - and not being all that God-fearing, I might still have my eyebrows raised a wee bit when I read some things about that racist church which the chosen one attended in Chicago for some 20 years...
Anyways, I just mean to say that your left wing kin might have deeper/varied reasons as to why they aren't voting Obama - and instead are choosing to vote for someone who had least showed Hillary! some modicum of respect over these past few years.
They’re not really that left wing, actually.
They voted for McCain in the 2000 primary, and their views of Bush hasn’t really improved since then.
I guess they think Hillary might be more to the right than what is actually true, and they can see 0bama for what he is...a radical left winger who hates what this country has been and is hell bent on the wrong kind of “change.”