I don’t know how it is in Arizona, but here in Ohio if you are a registered voter also listed is your party affiliation. It is a matter of public record, a simple perusal of his voter registration would reveal his political leaning. I’m guessing demoNcrat.
Loughner registered to vote for the first time in 2006, said Chris Roads, Pima County's registrar of voters. He registered as an independent and last voted in the 2008 general election.
article says he registered independent first time 2006, last voted 2008. I looked over Pima County Board of supervisors, other county offices, didn’t see same last name, but I hurried.