The Obama administration, grappling with a spate of recent Islamic terrorism cases on U.S. soil, has concluded that the country is confronting a rising threat from homegrown extremism.
The warnings point to a threat more immediate than that posed by terrorism from overseas, because U.S.-based militants are frequently American citizens who are able to travel freely and strike at home or abroad. The growing administration concern comes at a time when anti-terrorism officials and experts have pointed to signs of accelerated radicalization among American Muslims, a trend driven by online propaganda and the influence of foreign networks.
Until recently, Europe has been the front line for Islamic terrorist activity, while the U.S. remained relatively calm. But the number, variety and seriousness of recent U.S. cases make 2009 seem the most dangerous year in this country since 2001, anti-terrorism officials and experts say.
"We've seen an increased number of arrests here in the U.S. of individuals suspected of plotting terrorist attacks, or supporting terror groups abroad such as al-Qaida," Homeland Secretary Janet Napolitano said in a speech in New York Wednesday. "Home-based terrorism is here. And, like violent extremism abroad, it will be part of the threat picture that we must now confront."
Anti-terrorism officials say one of the most serious threats since the Sept. 11 attacks was an alleged al-Qaida bomb plot involving an Afghan-American arrested in New York in September. There have been five other cases involving Americans accused of contact or training with foreign networks. The FBI also has rounded up accused homegrown militants from Detroit to Dallas.
Several prosecutions are pending and not all motives are known. For instance, Maj. Nidal Malik Hasan, accused of killing 13 people in a Fort Hood shooting rampage last month, apparently suffered from emotional problems but was also driven by extremist beliefs.
A previous attack on the U.S. military, a shooting spree by an American convert who killed a soldier and wounded another at a recruiting center in Arkansas in June, was a case of a lone-wolf extremist.
"You are seeing the full spectrum of the threats you face in terrorism," former Homeland Security Secretary Michael Chertoff said in an interview.
Searching for causes for the apparent upsurge in the United States, anti-terrorism officials say intensified radicalization among American Muslims is a key factor.
"Radicalization is clearly happening in the U.S.," said Mitchell Silber, director of analysis for the Intelligence Division of the New York Police Deptartment, in an interview. "In years past, you couldn't say that about the U.S. You could say it about Europe."
Hard borders helped the United States ward off the threat. But experts also said that Islamic radicalization is more widespread in Europe.
In contrast, American Muslims are wealthier, better-educated and better-integrated because the United States does a good job of absorbing immigrants and fostering tolerance, experts say.
Nonetheless, recent investigations have run across suspected American operatives of al-Qaida and its allies who underwent training overseas, a formative experience that cranks up the potential threat. Suspects include a Latino convert from Long Island, N.Y., captured in Pakistan late last year; a Chicago businessman accused of scouting foreign targets for a Pakistani network; and at least 15 Somali-American youths who returned to fight in their ancestral homeland.
"A larger trend has emerged that is not surprising, but is disturbing," Chertoff said. "You are beginning to see the fruits of the pipeline that al-Qaida built to train Westerners and send them back to their homelands. ... This underscores the central significance of disrupting the pipeline at its source."
The year saw a simultaneous increase in Americans accused of planning violence at home.
"There have been a half-dozen cases of individuals who, instead of traveling abroad to carry out violence, have elected to attempt to do it here," Silber said in recent congressional testimony. "This is substantially greater than what we have seen in the past and may reflect an emerging pattern." Some feel radicalization in the United States has been worse than authorities thought for some time.
"People focused on the idea that we're different, we're better at integrating Muslims than Europe is," said Zeyno Baran, a Turkish-American scholar at the Hudson Institute. "But there's radicalization, especially among converts, newcomers, such as the Somali case shows. I think young U.S. Muslims today are as prone to radicalization as Muslims in Europe."
In proportion to population, extremism still appears less intense in the United States. But the Internet functions as the global engine of extremism. Web sites expose Americans to a wave of slick English-language propaganda from ideologues such as Anwar Awlaki, the Yemeni-American described as a spiritual guide for the accused Fort Hood shooter and for other Westerners.