Steven Emerson, the self-styled terrorism expert, has enjoyed quite a rebound since Sept. 11. Best known for his 1994 PBS documentary "Jihad in America," which painted an ominous picture of Muslim terrorists and terrorist sympathizers lurking in the United States, Emerson has always been highly controversial. His defenders see him as a voice crying in the wilderness; critics accuse him of being a propagandistic crank. After he went on TV to suggest, immediately after the 1995 Oklahoma City bombings, that Muslim terrorists were responsible, many mainstream news organizations shunned him. But since the Sept. 11 attacks, Emerson is suddenly being embraced as that slightly eccentric uncle we all should have paid more attention to. Because, the conventional wisdom now goes, Emerson has been vindicated by last year's terrorist attacks. He tried to warn us about Islamic terrorists among us but we, as a nation, were too complacent to listen.

Lately, television cannot get enough of Emerson, who's always quick with a quip and offers up "expert" commentary that usually goes unchallenged by hosts and guests. He works as a consultant for NBC News, but is regularly booked by Fox News. CBS's "48 Hours" recently aired a segment on him, playing up the fact that, for security reasons, visitors to Emerson's Investigative Project headquarters must be blindfolded first and staffers have to remain anonymous. (Why, if safety is such a concern, Emerson is willing to sit in front of any television camera with a red light flashing, or remains a regular on the speaking tour, was never addressed.)

Now Emerson is trying to cement his Cassandra image -- and capitalize on it -- with "American Jihad: The Terrorists Living Among Us," a quickie, large-print book that, minus the appendices, totals just 175 pages. This sensationalistic, poorly reasoned book will do nothing to enhance Emerson's stature among serious scholars. The "expert" who emerges from "American Jihad" is a heavy-handed scaremonger who fails to grasp -- or deliberately blurs -- the most rudimentary distinctions between different radical groups, asserting, for example, that the militant Shiite group Hezbollah, which is now a major political party and social services network in Lebanon, poses the same threat to America as al-Qaida. Whether this egregious conceptual flaw, which renders most of his book all but worthless, is the result of a political agenda to demonize passionate supporters of the Palestinian cause as terrorists or terrorist sympathizers, or is simply the result of hysteria and/or ignorance, is unclear.

For a decade, Emerson has been issuing dire, over-the-top warnings that Muslims in America -- many of them supporters of radical Palestinian groups like Hamas and Islamic Jihad -- pose a catastrophic threat to the country. According to Emerson, Americans face a hideous threat in our own backyard: sophisticated, stateside Mafia-like Muslim groups that have been brazenly funding terrorist activities, infiltrating universities, recruiting killers, plotting attacks and waiting for the signal to rise up. He would like us to believe that Sept. 11 proves he was right all along. But it doesn't.

Sept. 11 obviously proved that one militant Islamic fundamentalist group does pose a deadly threat to the United States. But Emerson wants us to think they all do, and that they're working together -- yet there is no evidence to support either claim. In fact, with the exception of al-Qaida and the group that carried out the 1993 World Trade Center bombing, none of the groups and organizations Emerson denounces have ever carried out terrorist attacks in America, nor does Emerson present any evidence that they intend to do so. Nor does he provide any evidence that the terrorists who carried out the 1993 and 2001 attacks were welcomed by the American Muslim community at large, were shielded while they plotted their attacks or assisted in any way. Finally, there's nothing in "American Jihad" to suggest any American-based Muslim organization had anything to do with, or had any advance knowledge of, the attacks.

"The Hamas of Palestine, Hizbullah of Iran, the Islamic Salvation Front and Armed Islamic Group of Algeria, An-Nahda of Tunisia, the Muslim Brotherhood and al-Gama'at al-Islamiyya of Egypt, the Jam'at Muslimeen of Pakistan, and the Holy Warriors of the Philippines and Chechnya -- all share the same goal of an Islamic world," Emerson writes -- the context making it clear that he believes all of these wildly disparate groups are willing to use terror against the United States to achieve that goal. "In the past 12 years, however, these groups have achieved a new level of coordination, owing to their exploitation of the civil liberties of the U.S." Emerson provides no evidence, except for a few scattered anecdotes, for this irresponsible claim -- one that, coming from a "leading terrorism expert," can be used to justify the ongoing erosion of Americans' civil liberties.

Of course, there have been, and may still be, terrorists among us. It's no secret that some of the al-Qaida terrorists were "sleepers" who lived in America for a long time, and that the terrorists who carried out the 1993 World Trade Center bombing lived here and made converts and contacts through a Brooklyn mosque. That's alarming, and worthy of serious investigation. And if there really are ties between anti-American groups like al-Qaida and, for example, mainstream Muslim organizations that support radical Palestinian groups, we need to know about them. Emerson claims there's a connection -- a murky, ominous one. But the ominousness is all in Emerson's overheated rhetoric. When you clear away the posturing, no connection emerges beyond their shared Islamic fundamentalism and shared views on Israel and Palestine.

Nor does Emerson's at times loose way with the facts inspire confidence. For example, he recounts the story of Ghazi Ibrahim abu Mezer, a Palestinian who in 1997 was arrested and charged with planning to bomb New York's subway system. That's a scary enough story, but Emerson wants to make it scarier, by tying Mezer to the radical Palestinian movement. Emerson writes that Mezer had applied for political asylum in the U.S. "on the grounds that he was in danger of arrest by Israeli law enforcement thanks to his membership in the Hamas organization." In fact, Mezer's application asserted that he had been falsely accused by Israeli authorities of belonging to Hamas. American law enforcement officials denied that abu Mezer was a member of Hamas, or that Hamas was involved in the bombing attempt in any way. James Kallstrom, head of the New York FBI office, at the time said "it is totally wrong to say that these individuals are connected to and directed by Hamas." Hamas also disavowed any involvement. Emerson fails to report any of this.

Emerson draws attention to the fact that many mainstream Muslim organizations and individuals in the United States raise money, give speeches on behalf of or otherwise support groups like Hamas and Islamic Jihad, which have terrorist branches that stage horrific attacks against Israeli soldiers and civilians. This is a legitimate point, but Emerson isn't satisfied with making it. According to him, Hamas and Islamic Jihad and all the other radical Islamicist groups aren't just fighting Israel thousands of miles away -- like al-Qaida, they're plotting attacks on America to achieve their dream of an Islamic world. Unfortunately, since there's no evidence to support this, Emerson has to fall back on conjecture: "As confrontation with the West heats up, Hamas operatives are ready to turn their formidable apparatus against American targets."

Emerson won't admit it, but radicals within the pro-life movement, for instance, have killed more innocent American civilians in the U.S. than has Hamas or Hezbollah or Islamic Jihad. Indeed, Emerson's book doesn't contain a single example of Hamas, Hezbollah or Islamic Jihad carrying out terrorist activities in this country.

That's because there are none, according to Vince Cannistraro, a former director of counterterrorism for the CIA. "Neither Hamas or Islamic Jihad, which have an infrastructure in the U.S, political organizations in the U.S., has ever targeted Americans here," Cannistraro told Salon. "It would be counterproductive to their cause. And their focus is Israel and occupied territories."

Robin Wright, author of "Sacred Rage: The Wrath of Militant Islam," agrees, noting the Palestinian groups "don't target the American embassy or consulate in Jerusalem. That's not what their goal is. Their focus is on Israel."

In fact, Cannistraro dismisses Emerson's entire thesis. "It's total bullshit," he says. "He's trying to say people who move to this country and set up charities and think tanks and are associated with Hamas and Islamic Jihad and Hezbollah, that there's some kind of connection between them and Sept. 11, that there's a liaison or support network. He doesn't know what he's talking about."

If there really was a vast network of Muslim fundamentalist terrorists within the U.S., one might expect that sooner or later intelligence agents and law enforcement officials would make a high-profile bust like the seven tons of rifles, pistols, submachine guns and rockets intercepted years ago off the coast of Ireland. A gift from American sympathizers, the load was enough to arm the outlawed Provisional wing of the Irish Republican Army for an entire year. Yet after a decade of sleuthing Emerson can't come close to documenting any kind of activity like that between American Muslims and Middle Eastern organizations. (Although Charlotte FBI agents recently busted a ring of people for allegedly using illegal cigarette sales to buy night goggles for the militant Lebanese-based organization Hezbollah.)

There's no doubt "American Jihad" does recall some chilling Islamicist terrorist attacks and would-be attacks -- like the thwarted subway bombing -- that would make any American shudder. Islamic terrorists clearly pose a threat to America. And if any terrorists are lurking among us, whether they swear their allegiance to Islam, Cuba, Northern Ireland, Puerto Rico or white supremacy, law enforcement should take whatever steps necessary to stop them. But Emerson is grossly inadequate as a guide to this field, which requires skilled analysis and an appreciation of complexities. Emerson, whose obsessive, sledgehammer approach makes his reporting often seem an afterthought to his conclusion, possesses neither.

Early in "American Jihad" Emerson tries to come across as a moderate, stating that Islamic extremists represent "but a tiny fraction of the total number of American Muslims." Yet in the very next paragraph he quotes approvingly from a source who insists Muslim extremists have taken over "more than 80 percent of the mosques that have been established in the U.S." And he fails to mention his 1995 claim in the Jewish Monthly that Islam "sanctions genocide, planned genocide, as part of its religious doctrine," or his warning in the Jerusalem Post that "the U.S. has become occupied fundamentalist territory."

Emerson does acknowledge his most famous gaffe, his erroneous suggestion that Muslim terrorists were behind the bombing of the Oklahoma City federal building in 1995. "That ended up being an albatross around my neck," he laments. But rather than learning from his rush-to-judgement mistake, Emerson instead wants credit today for not pushing the lunatic-fringe conspiracy theory that Oklahoma City bomber Timothy McVeigh was actually a front man for Muslim hate groups.

As the Oklahoma City bombing illustrated, for someone who has dedicated his adult life to tracking terrorist activities, Emerson has a pretty shaky track record when it comes to analyzing attacks. Following the 1993 World Trade Center bombing he told CNN viewers Yugoslavs were the likely suspects. And the next year, when TWA Flight 800 plunged into the Atlantic Ocean just off Long Island, Emerson was sure a bomb had brought it down. Neither theory turned out to be accurate.

But Emerson revels in theories, especially when he appears on TV, and especially on Fox News' "O'Reilly Factor," where excitable guests are urged to let their imaginations run wild when Muslims are involved. (When O'Reilly says, "We're speculating now, of course, and we don't like to do that on 'The Factor,'" it's one of TV's great unintended laugh lines.)

For instance, on Feb. 15, Emerson appeared to discuss the strange, sad story of Katherine Smith, a 49-year-old Tennessee motor vehicles inspector who late last month was arrested for helping five Middle Eastern men obtain fraudulent drivers licenses. One week later, she died after her slow-moving car burst into flames the night before she was to be arraigned in court, and law enforcement authorities began to ask questions about foul play and arson. (All five Middle Eastern men were in custody at the time of Smith's death.)

Emerson told host Bill O'Reilly that FBI agents were "definitely investigating whether this was a political assassination, meaning terrorists actually assassinated her." He added, "Definitely a firebomb, apparently, was put in the car."

Here's what's telling about Emerson's brief bit of "analysis":

A) In the nearly 100 hits found on Nexis regarding the Smith story, to date, not one law enforcement official ever used the word "assassination" to describe their investigation.

B) There is no evidence that any of the five Middle Eastern men who paid Smith $1,000 for licenses were "terrorists," as Emerson instantly dubbed them.

C) An FBI spokesman told the New York Times there was no evidence of an explosive device involved in the accident, which eliminates Emerson's bomb theory.

D) Along with homicide, Tennessee officials are also looking into the possibility of suicide. That's because Smith, a single mother, left her sleeping child at home and drove by herself after midnight to a rural stretch of highway south of Memphis. And because her clothes were later found to have traces of an accelerate, perhaps gasoline. (Witnesses saw nobody else at the scene.) Emerson, though, never uttered the word "suicide" on the air. He only wanted to talk about political assassinations plotted by Muslim terrorists.

In addition to chapters on terrorist networking, the first World Trade Center bombing, Hamas and Osama bin Laden, "American Jihad" devotes a chapter to Sami Al-Arian, the Kuwaiti-born computer science professor at the University of South Florida and fervent supporter of the Palestinian cause whom Emerson has been hounding for nearly a decade. Emerson first labeled the professor a terrorist in the 1994 PBS documentary "Jihad in America." Emerson pointed to two nonprofit groups Al-Arian headed up, one of which had an official affiliation with USF, and insisted they were "fronts" for terrorists. The organizations, which were shut down in 1995, were connected to fundraising for the Islamic Jihad.

The author then did a document dump at the Tampa Tribune, which has run nearly 100 Al-Arian-related news articles and editorials since. Salon recently dissected the paper's dubious reporting on the topic, illustrating how despite the Tribune and Emerson's endless crusade to brand Al-Arian a terrorist, or at least a terrorist sympathizer, to date there simply is no credible proof to back up the claim.

Immigration Judge John McHugh agreed. In 2000, after looking at the government's evidence regarding fundraising for terrorists and operating "fronts" for them at USF, the former military judge ruled there was no evidence to support it. The government appealed the case to an executive three-judge panel in Washington, D.C. which refused to overrule Judge McHugh.

Emerson's response to McHugh's decision? "The judge's ruling was in total error," he told "48 Hours." ("American Jihad" omits any mention of the judge's decisive, 56-page ruling as it pertained to Al-Arian.)

There was also the University of Florida's investigation, led by the former president of the American Bar Association, which found no evidence that Al-Arian, or his USF organizations, had terrorist ties. Emerson's response? "A whitewash." That's what he told an audience of Florida Holocaust Museum supporters last month.

It seems Emerson alone is able to uncover dastardly deeds in Tampa, but the FBI, the CIA, the INS, the Tampa police, USF and the courts cannot. (At least he no longer publicly suggests Al-Arian was involved in the 1993 World Trade Center bombing.)

Meanwhile, it's telling that in an entire chapter dedicated to illustrating how Muslim radicals have infiltrated American faculties ("Jihad in the Academy"), Emerson manages to offer up exactly one example: his already dubious charge against Al-Arian and USF. And the fact that Emerson uses the Al-Arian case in his book as the centerpiece ("perhaps the most disturbing case") of just how deep and troubling Muslim terrorism roots run in America tells readers all they need to know about Emerson's sourcing and reporting.

Last fall, a public firestorm erupted after Al-Arian was subjected to an belligerent, McCarthy-like grilling on Fox News' "The O'Reilly Factor," which concluded with the right-wing host essentially accusing Al-Arian of being a terrorist. Death threats poured in to the university. The university's president Judy Genshaft soon gave notice, over the strident objection of USF's faculty, that she intended to fire the professor. (At a recent appearance before the local Rotary Club, Genshaft recommended members read Emerson's "American Jihad" to better understand her position.)

(Last week, the U.S. Attorney in Tampa, in a highly unusual move, released a two-sentence statement stating that his office was conducting an ongoing investigation "into the conduct and activities" of Al Arian.)

Reporting on American Muslims' support for groups like Islamic Jihad and Hamas is a legitimate enterprise. But Emerson's complete failure to distinguish between mere rhetoric and actual participation in terrorism, and his inability or unwillingness to acknowledge the political dimension of the Arab-Israeli conflict, give his reporting a biased and one-dimensional tone.

The truth is, Emerson uses the word "terrorist" the way Sen. Joseph McCarthy used to use the word "communist." Trying to discredit as terrorist sympathizers the Council on American-Islamic Relations, one of the country's largest Muslim-American groups, and one that has been welcomed into the White House in recent years, Emerson writes the group once "co-sponsored an incendiary rally" that featured "anti-Jewish rhetoric." Time and again "American Jihad's" "proof" of terrorist ties is based on rhetoric, published articles and "incendiary comments" -- otherwise known in America as free speech. To be certain, some of the Islamic calls to battle Emerson cites are chilling, and Muslims in American need to seriously reconsider, for both moral and political reasons, whether they have pushed the boundaries of hateful rhetoric too far. (Judging by Emerson's own reporting they are; most of the most inflammatory passages included in "American Jihad" are dated, stretching from the late '80s to the mid '90s.)

But to suggest, as Emerson does in "American Jihad," that militant Muslims groups around the world, including those battling Israel, are targeting Americans at home, simply creates confusion and anxiety, especially among casual readers and TV viewers who have only a passing knowledge of the topic.

Then again, perhaps confusion and anxiety were Emerson's goals from the start.

Editor's Note: This story has been corrected since it was published.