Stewart Rhodes, the founder of a group called the "Oath Keepers," received applause for that line.
See the rant below, in the video from Right Wing Watch.
The Southern Poverty Law Center has a file on Rhodes as a leader of the "Patriot movement" ideology, which includes a description of Rhodes and the Oath Keepers:
The core idea of the group is that its members vow to forever support the oaths they took on joining law enforcement or the military to defend the Constitution. But just as central is the group’s list of 10 “Orders We Will Not Obey,” a compendium of much-feared but entirely imaginary threats from the government — orders, for instance, to force Americans into concentration camps, confiscate their guns, or cooperate with foreign troops in the United States. These supposed threats are, in fact, part of the central conspiracy theory advocated by the antigovernment “Patriot” movement of which the Oath Keepers is a part — the baseless claim that the federal government plans to impose martial law, seize Americans’ weapons, force those who resist into concentration camps, and, ultimately, push the country into a one-world socialistic government known as the “New World Order.” In 2013, the group took on a more aggressive stance, announcing the planned formation of “Citizen Preservation” militias meant to defend Americans against the New World Order.Also on the board of directors of the Oath Keepers is former Graham County Sheriff Richard Mack, who got a lot of attention by teaming up with Nevada rancher Cliven Bundy, who was in a standoff with federal agents over his refusal to pay grazing fees. Mack and Arizona Senate President Andy Biggs reportedly also spoke at the event.
As you can see in the video above, Rhodes' reasoning for his comments was because McCain has supported indefinite military detention, which many "Patriot" types believe is going to be used on regular American citizens. By contrast, Rhodes offers up to give McCain a trial for treason, and hang him afterwards.
The SLPC has more background information on Rhodes, including some of his more memorable quotes, like referring to Hillary Clinton as "Hitlery."
Got a tip? Send it to: Matthew Hendley.
Follow Matthew Hendley at @MatthewHendley.