When talk radio roars, Washington listens. Often, though the power brokers on Capitol Hill don't like what they hear.

As the nation's talkers relentlessly exposed the flaws in the Senate's comprehensive immigration reform bill, a visibly frustrated Sen. Trent Lott (R-Miss.), lashed out. "Talk radio is running America," he fumed, adding "we have to deal with that problem." Lott quickly clarified that the remedy he had in mind was better communication with voters, not governmentally-imposed restrictions on free speech. But other senators do want more regulation.

Sen. Dianne Feinstein (D-Calif.), for example, recently called for the reinstatement of the so-called "Fairness Doctrine," an obsolete federal regulation that, until its repeal in 1987, required stations to air all sides of controversial issues or risk the loss of their broadcast license. "Talk radio," she complained, "tends to be one-sided" and "pushes people to, I think, extreme views without a lot of information."

The one-sidedness to which she refers is the overwhelming success of conservative talk radio personalities including Rush Limbaugh (13.5 million weekly listeners), Sean Hannity (12.5 million), Michael Savage (8.5 million), Dr. Laura Schlessinger (8.0 million), and Laura Ingraham (5 million). Compare that to the abject failure of their liberal counterparts: the highest rated liberal talker, Ed Schultz, attracts 3 million weekly listeners.

Feinstein's frustration is shared by Sen. John Kerry (D-Mass.). "One of the most profound changes in the balance of the media," Kerry mused, came "when the conservatives got rid of the equal time requirements," which allowed them "to squeeze down and squeeze out . . . opposing views."

Those who are tempted to dismiss all this received a jolt last week when Sen. Dick Durbin (D-Ill.), the second most powerful Democrat in the Senate, announced flatly that, "It is time to reinstitute the Fairness Doctrine."

In fact, the opposite is true. There are many reasons why the Fairness Doctrine should remain shelved, but let's focus on two, the practical and constitutional cases against it.

First, as my Heritage colleague James Gattuso writes, "the real effect of the Fairness Doctrine was to discourage discussion of controversial issues of any kind." Station managers quickly realized that free-wheeling, ideologically-tinged programming would expose their stations to costly Federal Communication Commission regulatory proceedings. "As a result," Gattuso observes, "policy discussion on the airwaves for decades was…as bland as cottage cheese."

In its decision to jettison the Fairness Doctrine, the FCC commissioners explained that "we believe that the role of the electronic press in our society is the same as that of the printed press." Over the next 16 years the number of stations with talk formats more than tripled. There are now more than 1,400 such stations, making up a new and powerful media outlet.

Talk radio by any standard is decidedly conservative. A recent study by two liberal think tanks calculated that 76 percent of the political talk radio programming in the top ten markets is conservative.

Meanwhile, the executives of Air America, the heavily-hyped liberal-talk radio outfit, sheepishly filed for bankruptcy in October as WLIB, its flagship station in New York City, traded its all-liberal talk lineup for a more commercially viable gospel format.

Still, just as conservative views dominate talk radio, the liberal voice comes through loud and clear on the Internet. In fact, the audience for the top dozen liberal blogs is three times that of the top 12 conservative ones. Yet none of the liberals calling for government regulation of talk radio see a comparable need to require liberal bloggers to devote "equal time" to their conservative compatriots. Nor do they call for ideological balance on taxpayer-funded (and unmistakably liberal) public radio.

The selective nature of this proposed restriction on free speech is nothing new.

As Supreme Court Justice Antonin Scalia noted in his dissent in the landmark McConnell v. FEC : "Who could have imagined that the same Court which . . . has sternly disapproved of restrictions upon . . . virtual child pornography, tobacco advertising, dissemination of illegally intercepted communications, and sexually explicit cable programming, would smile with favor upon a law [the McCain-Feingold campaign finance law] that cuts to the heart of what the First Amendment is meant to protect: the right to criticize the government."

Given the role conservative talkers played in the demise of the immigration bill, expect the number of lawmakers willing to "cut the heart out" of the First Amendment and stifle conservative talk radio to grow.

The welcome news is that Rep. Mike Pence (R-Ind.), a former syndicated radio talk show host, has introduced timely legislation to bar the FEC from resurrecting the Fairness Doctrine.

Michael Franc is Vice President for Government Relations at The Heritage Foundation.