Why conservatives are having mixed luck getting video of angry, violent liberals.

When I was in Wisconsin covering the protests of a budget bill that would slash union rights and powers, I stopped by a free "Non-Violence Training Session" that had been advertised on posters at the Capitol. The sessions had been going on for days, and were put on, for the most part, by activists from the Grassroots Leadership College in Madison.

The lesson was brief. I was actually the only person to show up on time, at 8 p.m. So I got my own rundown of the tips hundreds had received before me and hundreds have since. They started with a couple of questions.

"Why would you protest nonviolently?" asked my trainer.

I speculated that you might care for your fellow man. Or you might figure that protesting violently would tar your comrades by associations.

"That's right," she said.

On Friday, the three-week protest in Madison moved into a new phase, with activists peacefully leaving the Capitol, where they'd been sleeping, and planning more daily and weekend rallies. They got loud, and they shouted down legislators and Fox News, and they were photographed with signs comparing Scott Walker to Hitler. But they didn't get violent.

There was a lot riding on that. The Wisconsin showdown has, mostly, avoided becoming another skirmish in a tedious culture war—the battle between liberals and conservatives, both armed with cameras, to prove that the other side is hopelessly crude, violent, vile, Nazi-obsessed, and responsible for America losing its way.

Oh, it could have become that. On Thursday, Politico's Ken Vogel ticked off the many videos produced by Wisconsin Republicans and conservative activists who looked for video gold at the solidarity rallies held around the country. In Boston, Washington, and Atlanta, unidentified men shoved Tea Party activists who'd showed up to counterprotest union rallies. (The videographer in Atlanta responded to this with Hollywood timing: "Hey! He assaulted him! Right there! I want to file charges on that man!")

In Wisconsin, videographers had to settle for video of impolite signs: "Walker Sucks Koch," "Don't Retreat, Reload," Walker with the telltale Hitler mustache. The MacIver Institute, a conservative think tank, got a scoop when it captured doctors handing out sick notes to protesters who weren't sick. But it didn't film any violence. Christian Hartsock, a conservative videographer who'd filmed liberals at a California anti-Koch brothers rally and egged them on to describe the violent acts they wanted to commit on Justice Clarence Thomas, showed up in Madison to document the first big pro-union rally. He didn't see violence, either.