The Islamist radicalism that inspired young Muslims to attack their own countries – in London, Madrid, and Bali – has not yielded similar incidents in the United States, at least so far.

"Home-grown" terror cells remain a concern of US law officers, who cite several disrupted plots since 9/11. But the suspects' unsophisticated planning and tiny numbers have led some security analysts to conclude that America, for all its imperfections, is not fertile ground for producing jihadist terrorists.

To understand why, experts point to people like Omar Jaber, an AmeriCorps volunteer; Tarek Radwan, a human rights advocate; and Hala Kotb, a consultant on Middle East affairs. They are the face of young Muslim-Americans today – educated, motivated, and integrated into society – and their voices help explain how the nation's history of inclusion has helped to defuse sparks of Islamist extremism.

"American society is more into the whole assimilation aspect of it," says New York-born Mr. Jaber. "In America, it's a lot easier to practice our religion without complications."

In a nation where mosques have sprung up alongside churches and synagogues, where Muslim women are free to wear the hijab (or not), and where education and job opportunities range from decent to good, the resentments that can breed extremism do not seem very evident in the Muslim community. Since 9/11, however, concern is rising among Muslim-Americans that they are becoming targets of bias and suspicion – by law enforcement as well as fellow citizens. It's a disquieting trend, say the young Muslims – one that might eventually help radicalism to grow.

It's impossible to pinpoint the factors that produce home-grown terrorists, analysts say. But it's also impossible to ignore the stark contrast between the lives of Muslims in European countries where bombings have occurred and those of Muslims in America.

"What we have here among Muslim-Americans is a very conservative success ethic," says John Zogby, president of Zogby International in Utica, N.Y., whose polling firm has surveyed the Muslim-American community. "People come to this country and they like it. They don't view it as the belly of the beast. With very few exceptions, you don't see the bitter enclaves that you have in Europe."

Life in America vs. life in Europe

Part of what so shocked Spain about the Madrid train bombers, and then Britain after the London subway and bus bombings in July 2005, was that most of the perpetrators were native sons. In each case, the young men, allegedly inspired by Al Qaeda ideology, came from poorer neighborhoods heavy on immigrants. (By contrast, a plot foiled in August to blow up airplanes over the Atlantic involved suspects from leafy, middle- and upper-middle-class neighborhoods in Britain.)

America, too, has poorer neighborhoods with large Muslim concentrations, but they tend to be interspersed with other ethnic groups and better assimilated into society. Another difference, some suggest, is the general profile of Muslims who have come to the US and raised their families here.

Most Muslim immigrants came to America for educational or business opportunities and from educated, middle-class families in their home countries, according to an analysis by Peter Skerry of Boston College and the Brookings Institution. In Europe, the majority came to work in factory jobs and often from poorer areas at home.

European Muslims today live primarily in isolated, low-income enclaves where opportunities for good jobs and a good education are limited. In the US, 95 percent of Muslim-Americans are high school graduates, according to "Muslims in the Public Square," a Zogby International survey in 2004. Almost 60 percent are college graduates, and Muslims are thriving economically around the country. Sixty-nine percent of adults make more than $35,000 a year, and one-third earn more than $75,000, the survey showed.

In Britain, by contrast, two-thirds of Muslims live in low-income households, according to British census data. Three-quarters of those households are overcrowded. British Muslims' jobless rate is 15 percent – three times higher than in the general population. For young Muslims between 16 and 24, the jobless rate is higher: 17.5 percent.

"The culture is qualitatively different [in the American Muslim community] from what we've seen from public information from Europe, and that actually says very positive things about our society," says Jonathan Winer, a terrorism expert in Washington. "We don't have large populations of immigrants with a generation sitting around semi-employed and deeply frustrated. That's a gigantic difference."

Jaber, the AmeriCorps volunteer, who is studying to become a medical doctor, says he has not experienced anti-Muslim bias. In part, he says, that may be because he doesn't have an accent or look particularly Middle Eastern – his father is Palestinian and his mother Filipino. But he also credits America's melting-pot mentality, as does Ms. Kotb, the Middle East consultant.

"We weren't isolated growing up. We were part of the culture," says Kotb, who grew up outside Washington in a family that inculcated a success ethic. "Religion was important, but not so much that you'd have to cover your head or if you don't pray five times a day, that's it – nothing like that. There were a lot more progressive attitudes" within her local Muslim community.

In mosques in America, it's fairly common for imams to preach assimilation, says Mr. Zogby. That's not as true in Europe, particularly in poorer neighborhoods where sermons can be laced with extremism.

"The success of ... Saudi-inspired religious zealotry in Europe was in large part because the Saudis put up the money to build mosques and pay for imams," says Ian Cuthbertson, a counterterrorism expert at the World Policy Institute at the New School for Social Research. "The American Muslim community was rich enough not to require Saudi money to build its mosques."

In Europe, it's estimated that millions of second- and third-generation Muslims have not been well assimilated in their adopted countries, so have little or no fealty to either the European country they live in or the one their parents were born in. "They are much more susceptible to the Internet, returning jihadist fighters, and extremist imams," says Thomas Sanderson of the Center for Strategic and International Studies in Washington. "There's no doubt that Europe has an incubator environment and we have a somewhat sterile environment for radicalism."

To be sure, the United States has brought charges in several terrorism-related cases involving American Muslims. Some have resulted in convictions, notably the 2002 case of six Yemeni-Americans from Lackawanna, N.Y. Other cases are pending. (See chart on Page 2.)

Identifying and tracking home-grown terrorists is a complicated task – one that risks alienating or even infuriating the general Muslim-American citizenry if tactics are seen as unfair.

Feeling a chill

The young Muslims interviewed for this story chose their words carefully, but their inference is clear: They worry that suspicion toward Muslims has been building since 9/11, and they suggest that US intervention in Iraq and its support for Israel cause angst among many Arab-Americans.

US foreign policies "in the long term are going to hurt the US," says Mr. Radwan, the human rights activist, who works in Washington. "They, along with the crackdown on Muslim-Americans [by law enforcement], feed a feeling of resentment and the perception that the US acts on the basis of a double standard."

Indeed, America's Muslim community would wage the war on terror differently. According to the 2004 Zogby survey, three-quarters say the best way is for the US to change its foreign policy in the Middle East by recognizing a Palestinian state and being less supportive of Israel.

A newer concern for America's Muslims is their standing in post-9/11 society. Many sense that the ground under their feet is shifting – and young people like Florida-born Radwan, in particular, feel it. A 2001 graduate of Texas A&M University, Radwan wanted to become a doctor and began working as a medical researcher. One month after the 9/11 attacks, he was let go – at the end of a three-month probationary period. Afterward, he says, he couldn't get even an interview for a job that used his biochemistry degree or research skills. Eventually he abandoned his hopes of a medical career and shifted to human rights work.

That experience leads him to suggest another reason the US hasn't seen European-style homegrown terror cells: the intense scrutiny the FBI has focused on Muslim-Americans. "That is good in the short term, but bad in the long term," he says. "The Bush administration policies feed resentment that ... will stay in the Arab- American psyche for a long time."

The FBI says it doesn't target any community, neighborhood, or religion. Agents simply go where the leads take them, says John Miller, the FBI's assistant director of public affairs. But he adds: "We have put a growing effort into community outreach because we understand the discomfort the amount of pressure our attention can bring to a community."

The 'home-grown' threat: Is it overstated?

A small but growing number of analysts believe that some US officials have overstated the threat of homegrown Islamist radicalism in the United States. While Al Qaeda and foreign terrorists remain determined to attack in America, they say, the focus on potential American cells may be leading the US to misdirect its antiterror efforts.

"My theory as to why we haven't found any [homegrown Islamist terrorist cells] is because there aren't very many of them.... They aren't the diabolical, capable, and inventive people envisioned by most politicians and people in the terrorism industry," says John Mueller, a political scientist at Ohio State University. "The danger is that we've wasted an enormous amount of money with all of the wiretaps [and] investigations, and diverted two-thirds of the FBI from criminal work to terrorism work."

The FBI calls such conclusions "uninformed," citing alleged plots by radicalized US citizens. The most notable was the case of the Lackawanna Six, so named for the six Yemeni-Americans from Lackawanna, N.Y., who went to Al Qaeda training camps in the spring of 2001.

"The people who make these claims [about threats being exaggerated] are never the ones responsible for preventing these attacks," says John Miller, the FBI's assistant director of public affairs. "The point is that if you're the dead guy, or you're a family member of one of those guys, all you know is that you wanted someone to develop the intelligence and take the actions to prevent it."

Still, a lack of public evidence pointing to extensive Islamist extremism in the US is leading a small but growing number of experts to agree with Professor Meuller's assessment. Like Meuller, though, they add a cautionary note.

"There's not zero threat in any community, but it is good news and we have to hope that reflects an underlying reality that [homegrown extremist cells] don't exist here," says Jonathan Winer, a terrorism expert in Washington. "You've always got lone nuts in every imaginable ethnic group grabbing every imaginable ideology to justify terrorism."