Recycling is supposed to be a good thing, so you'd think that media organizations would be proud when they do it. But in fact, they tend to keep it quiet.

I'm not talking about aluminum cans here, but about the tendency of media organizations to turn press releases and written-to-order opinion pieces into apparently objective accounts. This happens all the time, partly because of media laziness, and partly because of ingenuity on the part of the various advocacy groups that depend on media coverage to advance their agendas and promote their fundraising campaigns.

The first part of this formula, media laziness, was demonstrated by journalism students here at the University of Tennessee a few years ago. They produced a fake press release for a non-existent student group opposed to political correctness and sent it to various news organizations. Some ran the item; some even embellished the report of an event that never happened with additional details that weren't in the phony press release. None called the contact number (which was genuine) or did anything else to check its validity. Yet when they were exposed, their response was to call the experiment "unethical."

Meanwhile an apparent plagiarism scandal at two California newspapers was resolved when it turned out that the two columnists who published identical columns hadn't copied each other — they had both simply copied their columns word-for-word from the same press release. Oh, said the editors. That was OK.

The second part, interest-group ingenuity, is illustrated by the recent efforts by gun control groups to capitalize on the terrorist attacks of Sept 11. The first round was a flop, as Tom Diaz of the Violence Policy Center tried to bolster an ongoing campaign against high-powered rifles with bogus claims that the Barrett Arms Company had sold some of its .50-caliber single-shot rifles to Usama bin Laden. Not many fell for this one, which gave off a pronounced odor of fish, and The Washington Post even reported, accurately, that the rifles in question had actually been sold to the United States government.

But Sarah Brady's "Brady Campaign" (formerly Handgun Control Inc., and before that the National Coalition to Ban Handguns) took a different tack. In a daring non sequitur, the Brady Campaign argued that the smashing of two hijacked airlines into large office buildings clearly made the case for ... banning gun shows! Or at least for subjecting every kitchen-table firearms sale among friends to the full requirements of the National Instant Check System.

Their argument was that "our soldiers could be gunned down by foreign terrorists armed with firearms purchased at American gun shows." America's "lax" gun laws, we were told, were going to allow "terrorists to amass their deadly arsenals."

I've seen the footage of Al Qaeda warehouses full of howitzers, mortars and even tanks, and it boggles my mind to hear activists claim, or at least imply, that they came from gun shows. I've been to a few gun shows, and I've never seen even one tank for sale. Nor do I believe that the Sept. 11 hijackers got their box cutters at a gun show. A lot of other people must have had the same doubts, because the Brady press release didn't get a lot of attention.

The next step, however, was an opinion piece in the Post by former Clinton Justice Department official Eric Holder, who regurgitated the claims made in the Brady press release and a similar one from the Violence Policy Center. (Guest opinion pieces of this sort are often "placed" by advocacy groups and PR firms, who frequently write the pieces themselves, persuade a prominent person to sign on, and then "shop" the piece to various publications in support of a broader public relations campaign.)

Some time later, the Post's editorial board picked up the theme, with an editorial that closely tracked the Holder op-ed and the earlier Brady Campaign and Violence Policy Center press releases. National Public Radio ran a story that did the same, though it at least identified the source as anti-gun interest groups. And The Associated Press ran an item featuring anti-gun lawmakers who cited — you guessed it — the earlier news and op-ed pieces as proof that new legislation is needed, doing just what the anti-gun groups want.

This is a common pattern, and once you learn to recognize the signs you'll see it all over the place: Group issues press release; news stories and op-eds suddenly appear raising the same issues; and lawmakers pick up on these and "independently" decide there's a problem, often holding press conferences that generate still more news coverage until people forget where the story originated. This approach is used by activists across the spectrum, though it works best for left-leaning groups because editors and reporters, who tend to share those groups' views, are less likely to recognize, or care, that they're being used.

While this particular effort to capitalize on fears of terrorism as a means of shoring up the sagging gun control movement may well fail, it's a useful example in how things work. (If you want to observe for yourself, just spend a few weeks cruising the Web sites of groups like Brady, the VPC, the Children's Defense Fund, the Sierra Club, and so on, and comparing the press releases available there with news and opinion coverage for the same period.) The fact is that mainstream media organizations have been allowing themselves to be used by activist groups for decades, in ways that they don't fess up to their readers and viewers.

But there's a price in such behaviors. More and more people are catching on to this sort of thing, and it may explain why the reputation of traditional media organizations continues to slide. For while they continue to claim that liberal bias is a myth, an amazing amount of what traditional media groups do comes straight from the fax machines of left-leaning advocacy groups. As long as that's the case, their claims to exercise unbiased editorial judgment are going to ring very hollow.

Glenn Harlan Reynolds is professor of law at the University of Tennessee, and writes for the InstaPundit.Com Web site. The opinions expressed here are his own and do not come from any PR agency or activist group. Nor does he own a tank.