The shootings and deaths in Tucson: how to respond?

Was the shooting spree in Tucson, Arizona, caused by inflammatory rightwing rhetoric?  Or was it at least partly to blame?  Ewan MacAskill in the Guardian writes about the fierce debate in the USA about these questions.

I think that such crimes do not have one simple cause but that various causes can contribute.  It is obvious to me and surely to many US citizens that if guns are easy to acquire then angry people will find it easier to turn their hate into killing.  Preventing such crimes needs a multi-pronged approach.