Just after four o'clock this afternoon, police began pouring into St. Paul's Rice Park, which should be familiar to you if you've been watching MSNBC's live coverage of the Republican National Convention. History tells us that there's always a good dose of performance involved in political protests. And today was certainly no different. You had protesters angling to get captured in the camera frame as Chris Matthews hosted "Hardball" and you had Matthews endeavoring to ignore them. That's nothing particularly new. Much of the same happened, most notably, back during the heavily-reported protests around the Democratic National Convention in Chicago in 1968.

But in what seemed to me like a particularly modern twist, the police officer above cheerily captured video the action on his digital camera as he and his baton-wielding colleagues filed in to surround the park. It was a strange enough scene that is made the press -- which, of course, had itself swarmed around the police -- laugh. This was participatory, all around, with everyone rather clearly playing a part. But it did indeed seem like a performance, which gave it a sort of desultory predictability, kinda like the stories you hear these days about students holding parties just so they can put the photos up on Facebook.

The assembled crowd, heavily sprinkled with folks from the anti-war group Code Pink, marched in chanting "end the occupation" and "no more war." It swarmed in front of the MSNBC stage as Matthews interviewed Florida Republican Congressman Adam Putnam. As Matthews grilled Putnam on Joe Lieberman's loyalties, the crowed attempted to raise enough noise to interrupt the broadcast.

But Matthews was undaunted, soldiering on with his part of the performance. The only acknowledgment he gave the protesters when the cameras were on was a playful "look at this crowd here" as he went to commercial, and, later, an oblique reference to "an interesting group of Americans."

Matthews did, however, eventually let the protest get to him -- once he stepped off the stage and the cameras quit rolling. When some in the crowd began expounding loudly upon theories of September 11th as an "inside job" and tallying cost of the Iraq war, Matthews turned towards them and said rather angrily "you don't know what you're talking about!" After finishing a stand-up interview on the edge of the crowd, Matthews stalked out of the park while saying to a staffer, "all they want to talk about is the war. It's all they want to talk about."

And with Matthews gone and "Hardball" wrapped, the crowd -- and police -- dispersed.