Much has been written about the use of cross-hairs in various political campaigns, and whether this contributed to the Arizona shooting.
Just a small technical point - the loon who did the shooting used a Glock. The Glock does not come with a scope, so you don't see cross-hairs when aiming it. You see something more like this:
Why be picky? Because of all the ranting that the pictures of cross-hairs set this guy off. Somehow the association between the cross-hairs that you would see in an old fashioned rifle scope would make this bloke buy a pistol and shoot all and sundry.
Old fashioned rifle scope? Fancy modern sights employ a red targeting dot, like the sight picture below.
Cross-hairs are so 20th century. They're the sort of thing you find in a Norden bomb site on a B-17, not a modern weapon.
I hope they fry the guy by the way. Elections are the best way to remove a politician you disagree with.