Less watchdog than pit bull (and one who, without the technology of the 21st century, might have been just one more angry man shouting from a street corner), Mr. Breitbart altered the rules of civil discourse.

Mark Feldstein, a journalism professor at the University of Maryland, said that Mr. Breitbart “used the tools of invective and polemic to change the conversation, to try to turn it to his advantage.”…

A student of the tactics of the leftist organizer Saul Alinsky (if not his politics), Mr. Breitbart played defense by giving offense, subscribing to Alinsky’s theorem that “the real action is in the enemy’s reaction.” He wielded a network of conservative sources, including a number of members of Congress, four of whom spoke at his Washington memorial, to sow mayhem opportunistically…

At both the memorial and the after-party, stories about his relentlessness and love of argument were legion. In her note read at the memorial, his wife reminded the crowd that Mr. Breitbart was willing to engage and argue with anyone. “I came home one day to our first apartment to find a couple of Jehovah’s Witnesses,” she wrote, “trying to wrap up the conversation and get out.”