Although reading through the short list of assassins and would-be assassins published on the NPR site as a side-bar gives a slightly different impression, the gist of the research suggests that "assassinations of political figures were almost never for political reasons":
"It was very, very rare for the primary motive to be political, though there were a number of attackers who appeared to clothe their motives with some political rhetoric" ....
What emerges from the study is that rather than being politically motivated, many of the assassins and would-be assassins simply felt invisible. In the year before their attacks, most struggled with acute reversals and disappointment in their lives, which, the paper argues, was the true motive. They didn't want to see themselves as nonentities.
"They experienced failure after failure after failure, and decided that rather than being a 'nobody,' they wanted to be a 'somebody' " ....
Among the character profiles is one "FT," an anonymous predator presumably locked up but one who shared his motivations with the researchers:
"FT was a lonely, angry young man with few job skills, living with a mother who was ill with cancer and other ailments and who demanded his constant attention. FT was watching a television show about the state gubernatorial election when he suddenly thought, 'How weird it would be to assassinate the governor.' He then started to read and learn about assassination and assassins and spent the next 18 months preoccupied with selecting and shooting a national leader," study authors wrote. (No public information is available on whom FT attempted to assassinate or when.)The researchers also maintained that an easy assumption of insanity is just wrong:
"There's nothing crazy about thinking that if I attacked the president or a major public official, I would get a lot of attention. I would get a lot of attention. My goal was notoriety," [one of the researchers] says. "That's why I bought the weapon."
And most of the assassins and would-be assassins weren't totally disorganized by mental illness, either.
"They were quite organized .... Because one has to be organized — at least to some extent — to attack a public official."