evidence: Neither the White House nor Biden’s campaign provided evidence to back Biden’s statement that this kind of violence is "unheard of" in the U.S. The comment ignores that U.S. history shows numerous occasions during which political leaders were targeted by politically-motivated violence, including in recent years. [...] "America has a long history of episodic political violence, from violence against Catholics and immigrants by the Know Nothing party in the early 1800s, to the blood-soaked Kansas-Missouri borderlands in the abolitionist and slave fights of the 1850s, the Civil War, and then the fight against civil rights 1950s to 1960s," Kleinfeld said. She added that from 1963 to 1968 alone, assassins killed Malcolm X, Martin Luther King Jr., and both John F. and Robert Kennedy. [...] Sam Oliker-Friedland, executive director at the Institute for Responsive Government, a group that works to make government and elections more accessible, said, "Political violence has been a troubling, consistent issue, less driven by idealogues executing a strategy than troubled people with access to guns who read the news. And from the reporting I’m reading today, this fits that pattern."