For a number of years, the liberal armies of academia and some of the news media did a good job bottling up conservative ideas by branding them hateful, or divisive, or unworthy of serious discussion. That worked for a while, until the resulting pressure created an explosion of conservative talk radio and a booming industry in accusations of news-media bias.

The shoe has been rather on the other foot of late, and the conservative ranks are now gloating. With most of the nation solidly behind the war effort, and young Americans suffering and dying in Iraq, the more bizarre pronouncements of left-wing celebrities and anti-American academics are no longer being shrugged off. They have been met with the force of public opinion and the spending decisions of irritated consumers.

Indeed, it has become politically incorrect gratuitously to knock the president and question America’s moral authority. Some well-known examples:

• The Dixie Chicks, an immensely popular band, landed in the deep fryer when lead singer Natalie Maines told a London crowd as war approached: “Just so you know, we’re ashamed the president of the United States is from Texas.” Radio announcers called for a boycott, sales of their CDs plummeted, and the mere mention of their names prompted booing at the Country Music Television Awards.

• Columbia University assistant professor Nicholas DeGenova, at a public event, branded patriots as white supremacists and said that “the only true heroes are those who find ways that help defeat the U.S. military.” He added, “I personally would like to see a million Mogadishus” – a reference to the 1993 debacle in Somalia, when American troops were dragged through the streets. The university was bombarded with complaints, and its president said that DeGenova’s teaching “crosses the line.”

• Susan Sarandon and her partner, Tim Robbins, lost some gigs when people became fed up with their anti-war diatribes. Last week, the Baseball Hall of Fame canceled a celebration of their 1988 movie, “Bull Durham.” Dale Petroskey, president of the Hall of Fame, said that their “very public” criticism of the war could “put our troops in even more danger,” and he did not want to provide the pair with yet another platform.

• Sen. John Kerry, D-Mass., got pelted with criticism when he called for “regime change” in the United States, to go along with regime change in Iraq. Some people were offended at his drawing an implicit parallel between the butcher of Baghdad, a mass murderer who posed a threat to U.S. security, and the president of the United States – especially at the very moment when U.S. soldiers were risking their necks to free both America and Iraq from Saddam Hussein’s homicidal inclinations.

All this would seem to give credence to the observation of one of America’s most flamboyant critics, Gore Vidal: “For the average American, freedom of speech is simply the freedom to repeat what everyone else is saying, and no more.”

But of course freedom of speech is not worth much if people do not have the freedom to respond. That includes the freedom to refrain from buying a CD or the freedom to remember a politician’s inanities on Election Day. It even includes the freedom of an institution to withdraw an invitation – although the institution’s action will in turn be judged by the public. (The Hall of Fame is certainly looking remarkably petty for its snub of Sarandon and Robbins, imbecilic though their pronouncements often are.)

What the First Amendment does is prevent the government from stopping most speech. That is crucial, because even if private institutions and individuals attempt to stifle speech, ideas have a way of circulating – as long as the government stands back.

The First Amendment does not mean that one has the right to speak and bear no consequences for that speech. If people get angry at celebrities or radio talk-show hosts or newspaper columnists for spouting ill-informed propaganda, they have a perfect right to do so. Vidal may sneer, but some of what critics brand American close-mindedness is the propensity of people to talk back to “betters” who think their pontifications should go unchallenged.

Nevertheless, I would pray that Americans would refrain from boycotting and banning. We especially need to be on guard against powerful interest groups that want their side to be told, and no other. The First Amendment would be quickly eviscerated by the politicians if they perceived that citizens were getting into the habit of stifling or shouting down speech that offends them – liberal or conservative. It is human nature to feel uncomfortable about speech that challenges one’s prejudices. But it should be obvious that America’s great strength – as a nation and an inspiration – comes straight out of its tradition of fostering vigorous debate and the free flow of ideas.

We are best off when we open ourselves to ideas that clash with our own; when we consider the source (recognizing that celebrity or even academic title does not necessarily confer knowledge); when we listen to the argument; and when we come back with an argument of our own.

In fact, that’s what this newspaper page is all about.

Edward Achorn is the Providence Journal’s deputy editorial pages editor.