In essence he says even though all the historical incidents he cites have "political colorations", that does not mean they should be explained away by things like politically based: climate of hate, rhetoric, vitriol, extremism.
My question is: How does he know? Did he go back and research the general tone of discussions among politicians and common people? Or is he just making it all up as he goes along?
http://www.washingtonpost.com/wp-dyn/content/article/2011/01/10/AR2011011003685.html?hpid=opinionsbox1Instead, imagine a continuum from the rampages at Columbine and Virginia Tech - the results of individuals' insanities - to the assassinations of Lincoln and the Kennedy brothers, which were clearly connected to the politics of John Wilkes Booth, Lee Harvey Oswald and Sirhan Sirhan, respectively. The two other presidential assassinations also had political colorations.
On July 2, 1881, after four months in office, President James Garfield, who had survived the Civil War battles of Shiloh and Chickamauga, needed a vacation. He was vexed by warring Republican factions - the Stalwarts, who waved the bloody shirt of Civil War memories, and the Half-Breeds, who stressed the emerging issues of industrialization. Walking to Washington's train station, Garfield by chance encountered a disappointed job-seeker. Charles Guiteau drew a pistol, fired two shots and shouted, "I am a Stalwart and Arthur will be president!" On Sept. 19, Garfield died, making Vice President Chester Arthur president. Guiteau was executed, not explained.
On Sept. 6, 1901, President William McKinley, who had survived the battle of Antietam, was shaking hands at a Buffalo exposition when Leon Czolgosz approached, a handkerchief wrapped around his right hand, concealing a gun. Czolgosz, an anarchist, fired two shots. Czolgosz ("I killed the president because he was the enemy of the good people - the good working people. I am not sorry for my crime.") was executed, not explained.