After the immigration bill died and the Senate turned out its lights for the July Fourth recess, in the quiet you could almost hear the sound of the conservative talk-show hosts slapping one another on the back and clinking their champagne flutes.

In public, though, the pundits on the right were as bellicose as ever. “A crushing defeat for President Bush and the Senate’s Democratic leadership on amnesty, a glorious victory for the American people,” Lou Dobbs, who has arguably spent more time discussing immigration than anyone on the airwaves, declared on CNN the night of June 28, a few hours after the legislation’s supporters threw in the towel. “We did it,” proclaimed the headline on Rush Limbaugh’s Web site. “Amnesty bill goes down.”

Along with other conservative cable TV and radio hosts and like-minded bloggers, they had prompted so many calls that the Capitol telephone circuits had seized up earlier in the day, just before the pivotal vote. And the anger of those callers apparently had some resonance in the Senate, because in the end only 46 lawmakers stood behind the compromise measure, which would have combined beefed-up border enforcement and penalties for employers of illegal immigrants with a pathway to citizenship for many of the 12 million undocumented workers in the country.

Since then several media experts have been examining just how much credit the conservative talking heads should receive for the flameout of the immigration overhaul. Their answer is coming back as “plenty,” although with the caveat that — as a compromise pushed by a politically weakened President Bush — the legislation suffered from the lack of an equally fervent group of supporters.

The debate garnered a disproportionate amount of time on the talk shows compared with coverage it received in the mainstream media, according to studies by the Project for Excellence in Journalism, a research organization that uses empirical data to study press behavior. “It’s been a big story, but it’s been proportionally bigger among the talk shows,” said the associate director, Mark Jurkowitz. “There seemed to be an energy about this that you don’t see on all topics. It really felt like a de facto campaign.”

The PEJ found that in the seven weeks before the Senate set the bill aside, immigration was the second-most popular talk topic, trailing only the 2008 presidential campaign. In some weeks, immigration received 9 percent of all the news coverage in the mainstream media — but got 19 percent of talk-show time.

But a handful of opponents dominated the airwaves. In the final week, 75 percent of all the talk-show time devoted to immigration was controlled by Dobbs, Limbaugh and radio and Fox News host Sean Hannity. In addition, Jurkowitz noted, those hosts generally described the legislation “with the politically damning term ‘amnesty bill.’ ” Supporters fought that term — because the bill would not provide blanket forgiveness to past immigration law violators — but they had little ability to compete with the people in the studios, who generally get to decide what language will frame any public-policy debate.

As soon as they had their immigration victory, some of the conservative hosts moved on to an issue that would hit them closer to home. Citing comments by prominent Senate Democrats, including Dianne Feinstein of California and Richard J. Durbin of Illinois, they sought to rally listeners against any effort to bring back the federal “fairness doctrine,” which until its repeal in 1987 required licensed broadcasters to cover controversial issues in a balanced manner. “I know for a fact that Democrats were telling Republicans in the Senate yesterday, ‘Well, just go ahead and vote for this thing, by the time you’re up for re-election, we’ll have dealt with talk radio,’” Limbaugh declared on the air.

Though there were no apparent legislative or regulatory proposals to revive the fairness doctrine, Republican Mike Pence of Indiana, himself a former conservative radio host, quickly persuaded the House to add language to a spending bill barring the Federal Communications Commission from doing anything to bring it back.

“Talk radio is running America,” Sen. Trent Lott told The New York Times last month. That may be a bit of characteristic hyperbole from the Republican whip, but the immigration debate and subsequent fairness doctrine vote suggest that the on-air conservative talkers have considerable clout in the nation’s capital.

That’s not to say supporters of an immigration rewrite didn’t use talk radio, too: Spanish-language media were instrumental in helping turn out supporters at a series of rallies to promote the package. So the radio dial turns both ways. It just seems that one side has much more determined muscle, and better-positioned broadcaster allies, than the other. “Polls show that the overwhelming number of Americans can accept a solution much like what was on the table,” said Tamar Jacoby of the conservative Manhattan Institute. “But a small number of naysayers have been able to become the tail wagging the debate.”

Elizabeth Wasserman is a Washington freelance writer. She can be reached at ewasserman@cq.com.