This is a true story (as opposed to my usual falsehoods): A few years back, when the World Bank and International Monetary Fund would hold meetings of the planet’s finance ministers or other economic leaders, there would be angry demonstrations that sometimes turned violent. The different police agencies, local and federal, would plan well ahead and set up a heavily armed security presence.

It was tailor made for TV, of course, because we all knew what great video we’d get, and I’d usually end up going live from the middle of things, from some approved camera position nearby. In newsbiz, it’s a common experience, but it still can prove treacherous for those of us covering the melee.

At one of them, contrary to their public denials, the security forces fired tear gas at the advancing demonstrators, and we got video. One of the cops decided that he didn’t like the fact that we were taping, and first demanded we stop and then got pushy about it when we didn’t. He was on shaky ground; luckily, a supervisor intervened, and that was the end of it.

Actually, not quite the end of it. A few minutes later, that same policeman came over and asked when it would be on TV. When I told him I was about to go live, he asked whether he and his uniformed buddies could stand off to the side and see it. Some of them quickly called their families, and then they stood just out of the shot to watch the video on our monitor while I did my report.

That kind of rough encounter is common for journalists, although the happy ending is not always the way things work out. I’m among those who believe that most cops and other first responders are heroes who do a brutal and thankless job. But there are too many who are anything but. They can be bullies. They viscerally hate reporters for showing them doing stuff they shouldn’t be doing. They know that when they prevent us from doing our jobs, sometimes by forceful means and arrest, they may have to back off later, but they have prevented coverage that will inform citizens about what’s happening in a newsworthy situation. That way, they won’t be held accountable.

In a place like D.C., the authorities have extensive experience with large-scale confrontations. While there are abuses, they are conscious of what they should be doing and not doing.

That is obviously not the case in Ferguson, Missouri. Investigators will have to sort out what caused white officer Darren Wilson to fatally shoot black 18-year-old Michael Brown, who was unarmed. What we already know is that the Ferguson police were way over their heads in dealing with angry protesters. They responded in ways that could be charitably called insensitive. Bringing out the dogs was terrible symbolism — any fool should know that. Apparently some don’t.

Another problem is that these law-enforcement officials also mobilized massive military equipment. Their heavily armored forces looked like the robotic troopers in “Star Wars.” They used their arsenal to throw tear gas and shoot rubber bullets at the crowds, while arresting participants and reporters.

Their thuggery was so blatant, it caused official Washington to notice and to question whether police departments should even get the surplus battleground equipment that the Pentagon has been more than happy to provide them.

As we are constantly reminded, bad-apple cops nationwide sometimes violently exceed their authority. In any case, they are not supposed to be a militia. They’re not trained for that. They’re supposed to “serve and protect” face to face, not inside tanks. Our Posse Comitatus law prevents the armed forces from doing police work. In the Capitol, an unusually bipartisan collection of leaders is promising legislation that would limit access to battlefield equipment. Speaking of limits, apparently, some police officers need better training on what theirs are.

Bob Franken is a longtime broadcast journalist, including 20 years at CNN.