Tony Stark served briefly as W's SecDef in the comics. He wouldn't admit to being either a Democrat or Republican. Oliver "Green Arrow" Queen is an uber-lefty. Carter "Hawkman" Hall is a conservative. Wally "Flash" West was an admitted conservative in his Teen Titan days, but I don't know about now.
Ultimate Captain American is clearly a strong conservative. Mainstream Captain America and Superman are characters with old fashioned values and great patriotism, but they are portrayed as very tolerant of liberal ideas.
Wally West has fairly recently been shown as being a real middle class blue collar type of guy. He comes off fairly conservative but I would hazard to guess he votes for Dems.
His mentor Barry Allen was shown to be fairly rightwing (Though not as much as Hawkman). Though this is probably just a recon.
I never understood how Ollie could be a lib. He goes around shooting people with arrows!? Shouldn't he be pro-gun control?
Sick, sick, sick.