I'm sure there is some code in the DSM-IV that fits Jared Loughner, but for those of us less concerned with the niceties of psychological evaluations, the term "nut job" should do well enough. Judging by descriptions of young Jared by some who knew him at his community college in Tuscon, he was erratic, disruptive, and — especially when trying to express his most deeply held beliefs — completely incomprehensible.
I find it unlikely that the wack-a-doodle right wing populists of talk radio and TV had any influence on him at all — they are generally far too conventional, doctrinaire, and focused to have had all that much impact. Perhaps he culled a bit here and there from the darker recesses of the internet, but I think it most likely he concocted his own, personal set of paranoid delusions — "motives" that he might not be able to explain comprehensibly even if given the chance.
There will be plenty who will want him sentenced to death, and when I see photos of that dear little girl he murdered, I am not entirely unsympathetic to their point of view. In the meanwhile, though, we'll have to wait for the experts to decide whether he is lucid enough to participate meaningfully in his own defense.
I wonder if young Jared's parents, with whom he lived, ever noticed his deteriorating emotional condition, and if they ever considered finding him professional health. I wonder if the Tuscon Parks Department provides Mrs. Loughner with family health coverage, and if that coverage includes psychological benefits.
I wonder if it might be arranged for Jared Loughner to be cellmates with Theodore Kaczynski. Ah, what fascinating philosophical discourse might ensue!