This is the bloggers' hour. The blogs have exposed CBS, beaten the New York Times, and made fools of all the professional press critics at the Columbia Journalism School and the Poynter Institute. PowerLineBlog and Little Green Footballs and Instapundit and Hugh Hewitt: They have earned their garlands and their victory lap.

In the days ahead, there will be more work for them to do. There are still many unanswered questions--along with much arrogant spinning by CBS. But as the bloggers, reinforced by talk radio and the cable-news networks, force the truth to light, a word of caution.

There's an idea gaining traction out there that it's technology alone that has upended the old Big Media monopoly. According to this interpretation, computers and the Internet and cable television doomed CBS and the others from the start.

But that's not true. They have the same computers and the same cable technology in Europe, but there the old media companies still reign supreme. It's not technology alone that transformed the media: It's technology plus laws and rules that make it possible for the technology to be used. And those laws and those rules are under attack.

Think for a moment about your AM radio. Twenty years ago, AM broadcast pop music and news bulletins. Today it carries hours of conservative talk. What changed? Not the AM band--it functions exactly the same as it did in 1984 or, for that matter, in 1934. What changed were the rules. Up until 1987, any radio station that allowed time for partisan comment had to allot an equal amount of time to the other side--with the Federal Communications Commission deciding what counted as "the other side." Daunted by that regulatory burden, AM radio stayed away from politics altogether. It's not a coincidence that Rush Limbaugh emerged as a national voice only after the so-called Fairness Doctrine was abolished--and that liberal Rush critics have repeatedly tried to reinstate the old rule ever since.

Or think about the Swift Vets ads. Maybe you saw them on the Internet. But they were there for you to see only because senators John McCain and Russ Feingold failed in their attempt to amend U.S. election law to prevent citizens--like the veterans--from making their voices heard during election campaigns. As McCain's chief of staff, Mark Salter, explained soon after the 2000 election: "Growing numbers of members running for reelection feel they are losing control of their campaigns. It's not just independent-expenditure committees running ads against them that are the problem; it's the groups running ads for them that can turn out to be counterproductive, with uncoordinated messages which the candidates cannot influence."

You can soon expect to hear much sober chin-pulling about the "dirty" campaign of 2004--and the need once again to reform the campaign-finance laws so as to extinguish non-candidate election speech once and for all, as has been done in Canada and much of Europe.

That's one aftershock we can expect. Another is the continuing rise of liberal mistrust of the media, one of the most important ideological phenomena of the past four years. Bloggers, by themselves, would have little effect if talk radio and Fox News did not pick up and amplify their work. So Fox too now finds itself in the gunsights.

If you listen to mainstream Democrats--not frothing Chomskyites, but people who comfortably voted for Bill Clinton and Al Gore--you suddenly hear them sounding like Reed Irvine in 1977. And on the subject of Fox they become almost unhinged. Outfoxed, a documentary attacking the news network, opened on 2,800 movie screens in July and is being promoted by Democratic surrogate groups MoveOn.org and the Center for American Progress. Fox looms large in Dan Rather's paranoid fantasies: When a local Fox reporter cornered Rather at Dallas airport on Sept. 18 to ask whether he felt "duped," Rather snapped, "Do you feel like you were duped--working for Fox like you do?"

After criticizing Fox, liberal activists began attempting to compete with it: That seems at any rate to have been the idea behind Al Gore's new cable network. Its launch, however, promises to be a disaster: Gore's principal content is repackaged footage from the Canadian Broadcasting Corporation (not that there's anything wrong with that!). Should American viewers prove unresponsive to secondhand Canadiana, the critique of Fox may get more radical.

Technology does make certain changes possible. But law determines whether those possibilities become realities. Back in the 1980s, Ted Kennedy tried to manipulate antitrust policy to strangle Rupert Murdoch's emerging television empire. But since then, American law has tended to favor media upstarts and independent voices. Over the past half-dozen years, powerful liberals and Democrats have woken up to the harm that has been done them by the breakup of the old media oligopoly.

When John Kerry first appeared on the national scene, in the spring of 1971, the big networks made a celebrity and hero of him. On the White House tapes recorded at the time, President Nixon can be heard forlornly asking H. R. Haldeman and Charles Colson how they could challenge Kerry's allegations and get their own story out--but to little avail. In those days, the big networks, backed by the two big newsmagazines, and the three or four nationally influential newspapers, were more than a match for the power of the presidency.

As the networks have lost their power, so too has American liberalism. And one way to understand so much of what liberals now propose by way of "reform"--beginning with their highest priority, campaign-finance legislation--is as a series of attempts to curtail independent media and restore the old oligopoly.

And we will hear more about all of this after the election. Many liberals and much of the Left have persuaded themselves that the loss of media power is to blame for their loss of political power. They will be out to rectify that loss. They will seek, they are already seeking, ways to put an end to the media diversity that laid Dan Rather low. And nobody who values independence in media should delude himself that modern technology is invulnerable to control masked as "reform."

The onslaught is coming. Get ready for it.

David Frum is a resident fellow at AEI.