There's also a grey area where someone does something horrible and clearly politically motivated (shooting Reagan or Senator Giffords, shooting at Ft. Hood) and

There's also a grey area where someone does something horrible and clearly politically motivated (shooting Reagan or Senator Giffords, shooting at Ft. Hood) and that person has mental health issues. There's a semantic discussion about whether "lone gunmen" type attacks count as "terrorism", but categorizing motivations in real life as politics or insanity isn't so simple.