Protesters who bring guns to rallies where President Obama has been speaking are taking the national debate over healthcare and other issues to a new and dangerous level of concern. It's a frightening sign of how deep our divisions have become and what a bizarre turn our political debate has taken.

The presence of guns at a political event cannot be justified as a form of self-defense, freedom of expression or as a way to make a better argument. Guns at political rallies send a message of intimidation, or perhaps the bearer's political paranoia. Neither has anything to do with debating public issues.

How does packing heat at one of these events promote the free exchange of ideas? That's what townhall meetings are supposed to be all about, remember?

What message does it send for someone to show up at a site where the president of the United States is speaking with an openly displayed AR-15 automatic assault rifle, as one man recently did in Phoenix? At least a dozen people carrying weapons were in the crowd outside the arena where the president spoke.

They were staying well within the limits of the law in Arizona, but just because they can doesn't mean they should. Carrying a weapon into the arena of political protest introduces an element of intimidation and diminishes the right of citizens to participate in these events without fear of physical harm.

So far, the White House does not seem alarmed. The Secret Service enforces a prohibition against bringing weapons into the immediate vicinity of a president.

That doesn't make the presence of guns anywhere at these events a good idea. Freedom of expression doesn't confer on anyone the right to introduce loaded weapons into the arena of political protest. It's a punk tactic that's looking for trouble.