CNN has video of a protester carrying an AR-15 semi-automatic assault rifle outside an Obama event in Phoenix, Arizona today. The gunman told the media that the gun was loaded.

CNN's White House correspondent said he saw several other people carrying guns including another anti-Obama protester with an AR-15 who was screaming about socialism.

The Associated Press is reporting that a dozen people were openly carrying guns outside the Obama event.

This is the third gun-related incident at a presidential speaking engagement in the space of a week.

It's legal to openly carry a firearm in Arizona. So what? Taking a loaded assault rifle to a protest is naked intimidation. Whoever is organizing these militia mental midgets needs to call them off right now. They may be within their legal rights, but their behavior is profoundly anti-democratic.

Republican senator Thad Coburn went on TV yesterday to say that the state deserves the anger of teabaggers because it has made these people believe that they are about to lose control of their government. That kind of rhetoric plays into the paranoid fantasies of gun nuts steeped in the idea that they should use their guns in defense of liberty. Notice how Coburn and GOP leaders in polite company couch these statements in terms of what people think, as if they had no responsibility to tell their followers the truth or deescalate the situation in any way. If they had any interest in discourse or even safety, they would try to ratchet down the tensions by reminding people that just because they don't agree with the president doesn't mean he's on the verge of becoming a tyrant. Clearly they don't believe that Obama is an incipient dictator, they know he's not even committed to serious heatlhcare reform. He has already wavered on the public option. In his more radical moments the president wants to give the insurance industry subsidies and force the public to buy more of its crappy products. The GOP knows this perfectly well, but it won't exercise leadership to reign in its base. On the contrary, it's systematically and gleefully ratcheting up the tensions at every turn.

"People are concerned at the American way of life being threatened and business being vilified," former White House spokesperson Dana Perino said of the furious protesters disrupting town halls around the country.

The fevered theories of the birthers also reinforce the perception among the president's critics that Obama is not merely wrong but illegitimate. Signs reading "death to Obama" and "it's time to water the tree of liberty" have cropped up at town halls. (Thomas Jefferson famously wrote that the tree of liberty must periodically be refreshed with the blood of patriots and tyrants.) Glenn Beck has been likening Obama to Hitler on the air and Sarah Palin has been insisting that the president wants to kill her baby with Downs Syndrome. Between the sick rhetoric, the summer heat, and the guns, it's only a matter of time before someone gets seriously hurt.

Republicans and their lobbyist allies are riling up the militiamen. They don't care who gets hurt as long as the insurance industry's profits are safe.