“My thinking was when we beat them in 2012 that might break the fever, and it’s not quite broken yet,” President Obama remarked at a Democratic fundraiser in New York City on Monday. He was referring to relentless Republican attacks, including hyperventilating efforts to find evidence that will somehow reveal a sinister, potentially treasonous Benghazi plot by either the President or Hillary Clinton.

I’m not going to analyze efforts to unearth a Benghazi scandal. For a clearheaded, balanced, and succinct analysis, I refer you to Richard Cohen’s excellent column, Symptoms of Benghazi Syndrome, in the Washington Post. What I want to discuss is the fever generally.

I am not one who believes that the wild attacks on the President – about Benghazi and other things – are entirely politically motivated. Yes, of course, there are some Republicans who know better but nonetheless cynically manufacture or magnify claims for political advantage. Yet there are others on the right who make wild-eyed claims and on some level believe them. I am characterizing these individuals as being on “the political right” rather than being Republicans – even though many are prominent Republicans – because that’s what is most germane.

What’s the origin of the fever? What explains it?

The first thing to understand is that the modern conservative movement is, at a fundamental level, driven by fear. In my book about how William F. Buckley Jr. refashioned modern conservatism, I write:

“Buckley was leading a movement fueled by fear: fear of international communism expansion; fear of domestic communist infiltration; fear that American leaders were naïve or perhaps worse; fear that the civil rights movement would destroy civilization; fear that American capitalism would be devoured by socialism; fear that Americans would lose their self-sufficiency and become soft, self-indulgent, and dependent upon government largess; fear that America would embrace secularism and cease to become a nation under God.”

One of the things that made Buckley such an extraordinarily effective leader of the right was that he could simultaneously give voice to those fears and serve as an antidote to them. Buckley was an upbeat, cheerful, confident, and witty person. He did not appear afraid. Much the same may be said of the other great leader of the American right, Ronald Reagan – and, looking across the pond, of Margaret Thatcher as well.

This does not mean that Buckley was not afraid. He feared all of the things on that list, and more. Here, in fact, may be the two most consequential sentences Buckley ever wrote, appearing in the preface to God & Man at Yale, the book that made him famous:

“I myself believe that the duel between Christianity and atheism is the most important in the world. I further believe that the struggle between individualism and collectivism is the same struggle reproduced on another level.”

Take a moment to reread those two sentences. Here’s what Buckley is suggesting: The world faces a titanic struggle between Good and Evil. The fate of the world hangs in the balance. And part of that struggle is taking place in the realm of politics and economics. On the side of Good is “individualism,” the term Buckley then used for conservatism and an absolutist vision of laissez-faire economics. On the side of Evil is “collectivism,” which, as God & Man at Yale makes clear, includes not only communism and socialism but liberalism and Keynesian economics. John Maynard Keynes and his devotees may not be Stalinists or Satanists, but through mistakenness and naiveté they are doing the Devil’s work.

This sentiment is at the core of modern conservatism. For most, that’s what it is – a sentiment rather than a fully-conscious belief – though that does not make it less potent.

When one understands this, one can better understand why some on the right are perennially suspicious of liberal leaders and take to conspiracy theories like catnip. Are the decisions made by liberal leaders merely foolish and misguided – or motivated by something darker? What lies behind Whitewater? Did Hillary Clinton murder Vince Foster? Is climate change a ""great hoax"" perpetrated on the American public to increase government regulation and weaken the free market? Was Barack Obama born in Kenya? Is he secretly a Muslim or a socialist? What really were his relationships with Bill Ayers and Jeremiah Wright? Is he secretly immersed in Marxist Kenyan anti-colonial theology? Did Barack Obama subliminally intone “Serve Satan” during his acceptance speech at the 2008 Democratic National Convention? (More than three million viewers have watched this YouTube video suggesting that he did.)

By no means am I suggesting that all conservative fears are crazy. There are surely things about which we should be afraid, and many things about which we should be cautious. Conservative cautions, warnings, and fears – when sober and reality-based – make important contributions to American social and political debate. But fears can careen into paranoia. That has been happening increasingly over a decade or more, and we’re well past the point of its becoming unhealthy and destructive. And too often Republican leaders are trying to exploit rather than reduce the fever.

As I relate in my book, William F. Buckley Jr. took a considerable risk when, in 1965, he unequivocally denounced Robert Welch and the John Birch Society. Buckley was a staunch defender of McCarthyism (though he conceded that Joe McCarthy was himself often irresponsible), and Buckley was worried about communist spies and sympathizers in American government. But Buckley recognized the difference between the rational and the irrational. He was appalled by Welch’s claims that communist agents and fellow travelers included – among many others – the Secretary of State, the Director of the CIA, and the Chief Justice of the Supreme Court, not to mention Dwight David Eisenhower, then President of the United States.

In retrospect, Buckley’s excommunication of the John Birch Society from the conservative movement may seem an easy thing. It was not. The Society was quite large at the time, and many National Review editors, writers, key financial backers, and subscribers were members. In fact, because the Society was semi-secret and many members did not publicly reveal themselves, Buckley could not be sure just how many Birchers were within his own ranks.

Buckley did not take these risks to help the liberals who were then in power. He took these risks to excise a cancer and save conservatism.

Many responsible conservatives must realize that the illness has returned. This fever that threatens their movement will not break by itself. Denunciations by liberals and the media will only feed the fever. The medicine is for responsible conservatives to call loony-tune claims, wacky theories, and irresponsible attacks for what they are. Things will be more difficult today than when Buckley took on the Birchers. There is today no single individual who has the authority Buckley had then. Concerted action is required. Even in 1965 Buckley did not act alone. He enlisted a collection of prominent conservatives to join him in collectively denouncing Robert Welch and the John Birch Society. Compounding the difficulty today, the fever is more widespread. It is not confined to a single group. Lunatic claims and fact-less theories must be denounced as they arise, Whack-A-Mole fashion, even though conservatives who do this will be criticized for aiding and abetting liberal opponents and compromising short-term political advantages.

The long-term health of the conservative movement and the good of the nation are at stake. If the fever is to be broken, responsible conservatives should study – and follow – Buckley’s example.