Skip to main content
Part of complete coverage from

Jihadist terrorism in America since 9/11

By Peter Bergen and David Sterman, Special to CNN
September 10, 2013 -- Updated 1154 GMT (1954 HKT)
<a href='http://www.cnn.com/2013/04/16/us/boston-marathon-explosions/index.html?hpt=hp_t2'>The bombings in Boston</a> on Monday, April 15, 2013, serve as a cruel reminder that the U.S. has seen other terror attacks on home soil. <a href='http://www.cnn.com/SPECIALS/us/boston-bombings-galleries/index.html'>See all photography related to the Boston bombings.</a> The bombings in Boston on Monday, April 15, 2013, serve as a cruel reminder that the U.S. has seen other terror attacks on home soil. See all photography related to the Boston bombings.
HIDE CAPTION
Terror attacks on home soil
Terror attacks on home soil
Terror attacks on home soil
Terror attacks on home soil
Terror attacks on home soil
Terror attacks on home soil
Terror attacks on home soil
Terror attacks on home soil
Terror attacks on home soil
Terror attacks on home soil
Terror attacks on home soil
Terror attacks on home soil
<<
<
1
2
3
4
5
6
7
8
9
10
11
12
>
>>
STORY HIGHLIGHTS
  • Authors: Since 9/11, al Qaeda hasn't carried out a successful attack in the U.S.
  • They say the threat has evolved into a danger of homegrown extremists launching attacks
  • Study finds that the number of attempted attacks has been declining
  • Authors: Could the Boston bombings have been prevented through better intelligence?

Editor's note: Peter Bergen is CNN's national security analyst and a director at the New America Foundation. David Sterman is a graduate student at Georgetown University's National Security Studies Program. This article is adapted from "Jihadist Terrorism: A Threat Assessment," a report for the Bipartisan Policy Center's Homeland Security Project written by Peter Bergen with Bruce Hoffman, Michael Hurley and Erroll Southers.

(CNN) -- We are about to mark the 12th anniversary of 9/11. Since then, al Qaeda and its affiliated groups haven't launched a successful attack in the United States.

The Boston Marathon bombings in April, however, serve as a reminder that the United States still faces a terrorism threat from disaffected U.S. citizens and residents who are influenced by al Qaeda's ideology.

So what is the status of this kind of threat?

Peter Bergen
Peter Bergen

The good news is that the number of "homegrown" jihadist extremists who have been indicted or convicted has steadily declined over the past few years, according to New America Foundation data. Where there were 41 cases in 2009, there have been six so far this year.

The number of individuals indicted for plotting actual attacks within the United States -- as opposed to other terrorism-related crimes such as raising money for a terrorist group -- also declined from 12 in 2011 to only three so far in 2013.

In recent years, extremists plotting attacks against the United States have also shown little, if any, connection to foreign groups. None of the 21 homegrown extremists involved in plots against the United States from 2011 to so far in 2013 is known to have received training abroad.

Of these extremists, only one, Tamerlan Tsarnaev, one of the alleged Boston bombers, is reported to have had contact with foreign militant operatives, but it remains unclear to what extent, if any, those contacts played a role in the Boston attack.

This lack of coordination between domestic extremists and overseas groups is likely the result of two factors. First, the ability of terrorist organizations to coordinate with extremists in the United States has been reduced by policing efforts inside the country and counterterrorism operations abroad.

Is terrorism still a threat to U.S. families?

Second, Internet use among jihadist extremists enables them to come into contact with extremist communities abroad and be radicalized without face-to-face meetings.

Of the 45 "homegrown" jihadist extremists who were indicted, convicted or killed from 2011 to now, 18 are known to have communicated with other extremists over the Internet or posted materials related to their radicalization online.

The shift to plotting by individuals who lack ties to foreign groups poses a distinct type of threat -- plots and attacks that are more difficult to detect but are also likely to be of a smaller scale. And because of the measures now in place to prevent the acquisition of precursor chemicals and materials suitable for making conventional explosives, homegrown extremists have also often struggled to produce effective bombs.

Before the Boston Marathon bombings, homegrown jihadists in the United States had shown little success at producing explosives. Joseph Jeffrey Brice -- who has professed admiration for Osama bin laden and Oklahoma City bomber Timothy McVeigh -- almost killed himself in April 2010 when a homemade bomb he was constructing exploded prematurely.

A month later, Faisal Shahzad's car bomb failed to explode in Times Square, even though he had received explosives training in Pakistan.

If the Tsarnaev brothers built the bombs used in the Boston attack without guidance from jihadists abroad, it suggests that the difficulties other "homegrown" militants have had building or detonating explosives may have been overcome. On the other hand, the Tsarnaevs' successful bombmaking could just as easily have been a fluke.

While the number of terrorism-related indictments fell between 2009 and 2013, the number of terrorist incidents has stayed about the same -- about one per year -- though not all of them have been lethal:

-- In June 2009, Abdulhakim Mujahid Muhammad killed a soldier outside a recruiting station in Little Rock, Arkansas.

-- Five months later, Major Nidal Malik Hasan shot and killed 13 people at Fort Hood in Killeen, Texas.

-- Shahzad's 2010 attempt to bomb Times Square was foiled when his bomb did not ignite properly.

-- Yonathan Melaku's drive-by shooting of military facilities in Northern Virginia in 2011 produced no casualties.

-- The Boston Marathon bombers killed four and wounded hundreds of others in April 2013.

The incidents carried out by homegrown extremists continue to be limited in their lethality, and major operations such as the 9/11 attacks are well beyond the skills of even the most capable domestic extremists.

Additionally, no homegrown jihadist militant in the United States is known to have acquired or used chemical, biological, radiological or nuclear (CBRN) weapons in the past twelve years. This point bears repeating, as there has been considerable overheated commentary on this subject over the past decade. Of the 221 individual cases of jihadist extremism since 9/11, not one case involved an allegation of CBRN acquisition, manufacture or use.

However, the fact that jihadist extremists in the United States have shown no interest in CBRN weapons does not eliminate the need for securing potential sources of chemical, biological and radiological agents.

According to a count by the New America Foundation, since 2001, 13 extremists motivated by right-wing ideologies, one left-wing militant and two individuals with idiosyncratic motives have deployed, acquired or tried to acquire chemical, biological or radiological weapons.

For example, William Krar and Judith Bruey, two anti-government extremists, possessed precursor chemicals for hydrogen cyanide gas, which they discussed deploying through a building's ventilation system. They were arrested in 2003 and later pleaded guilty.

The threat from homegrown extremists to the U.S. homeland has been constrained in recent years by a variety of security measures. According to data collected by the New America Foundation, family members of extremists and members of the wider Muslim American community provided useful information in the investigations of about a third of the homegrown jihadist extremists indicted or killed since 9/11.

Noncommunity members provided useful reports of suspicious activity in another 9% of homegrown extremist cases, while an informant or undercover agent monitored almost half of all homegrown extremists.

The Boston Marathon bombing, however, demonstrate the potential for these security measures to fail when plotters have few, if any connections, to known terrorist groups.

Looking forward, a concern about the Boston attack is whether it represents an intelligence failure that could have been avoided through a better implementation of existing policies or a new trend where "lone wolf" extremism is largely undetectable with the existing systemic checks in place.

The threat from homegrown extremists has changed substantially in the past three years, becoming the province of fewer individuals who are less connected to foreign groups than was once the case.

Whether this remains the case will depend on law enforcement being able to successfully adapt to confront the threat from disaffected U.S.-based individuals motivated by al Qaeda's ideology as well as whether the past few years' counterterrorism successes against al Qaeda overseas can be maintained.

Follow us on Twitter @CNNOpinion.

Join us on Facebook/CNNOpinion.

ADVERTISEMENT
Part of complete coverage on
April 16, 2014 -- Updated 1201 GMT (2001 HKT)
Rick McGahey says Rep. Paul Ryan is signaling his presidential ambitions by appealing to hard core Republican values
April 16, 2014 -- Updated 1253 GMT (2053 HKT)
Paul Saffo says current Google Glasses are doomed to become eBay collectibles, but they are only the leading edge of a surge in wearable tech that will change our lives
April 15, 2014 -- Updated 1849 GMT (0249 HKT)
Kathleen Blee says the KKK and white power or neo-Nazi groups give haters the purpose and urgency to use violence.
April 16, 2014 -- Updated 1156 GMT (1956 HKT)
Sen. Sheldon Whitehouse and Rep. Henry Waxman say read deep, and you'll see the federal Keystone pipeline report spells out the pipeline is bad news
April 16, 2014 -- Updated 1153 GMT (1953 HKT)
Frida Ghitis says President Obama needs to stop making empty threats against Russia and consider other options
April 15, 2014 -- Updated 2129 GMT (0529 HKT)
Peter Bergen and David Sterman say the Kansas Jewish Center killings are part of a string of lethal violence in the U.S. that outstrips al Qaeda-influenced attacks. Why don't we pay more attention?
April 15, 2014 -- Updated 1641 GMT (0041 HKT)
Danny Cevallos says families of the passengers on Malaysian Airlines Flight 370 need legal counsel
April 14, 2014 -- Updated 1523 GMT (2323 HKT)
David Frum says Russia is on a rampage of mischief while Western leaders and Western alliances charged with keeping the peace hem and haw
April 14, 2014 -- Updated 1156 GMT (1956 HKT)
Most adults make the mistakes of hitting the snooze button and of checking emails first thing in the morning, writes Mel Robbins
April 14, 2014 -- Updated 1754 GMT (0154 HKT)
David Wheeler says as middle-class careers continue to disappear, we need a monthly cash payment to everyone
April 14, 2014 -- Updated 1155 GMT (1955 HKT)
Democrats need to show more political spine when it comes to the issue of taxes.
April 14, 2014 -- Updated 1555 GMT (2355 HKT)
Donna Brazile recalls the 50th Anniversary of the Civil Rights Act as four presidents honored the heroes of the movement and Lyndon Johnson, who signed the law
April 14, 2014 -- Updated 1317 GMT (2117 HKT)
Elmer Smith remembers Chuck Stone, the legendary journalist from Philadelphia who was known as a thorn in the side of police and an advocate for the little guy
April 13, 2014 -- Updated 1856 GMT (0256 HKT)
Al Franken says Comcast, the nation's largest cable provider, wants to acquire Time Warner Cable, the nation's second-largest cable provider. Should we be concerned?
April 11, 2014 -- Updated 1522 GMT (2322 HKT)
Philip Cook and Kristin Goss says the Pennsylvania stabbing attack, which caused grave injury -- but not death, carries a lesson on guns for policymakers
April 11, 2014 -- Updated 1906 GMT (0306 HKT)
Wikipedia lists 105 football movies, but all too many of them are forgettable, writes Mike Downey
April 11, 2014 -- Updated 1432 GMT (2232 HKT)
John Sutter and hundreds of iReporters set out to run marathons after the bombings -- and learned a lot about the culture of running
April 11, 2014 -- Updated 1649 GMT (0049 HKT)
Timothy Stanley says it was cowardly to withdraw the offer of an honorary degree to Ayaan Hirsi Ali. The university should have done its homework on her narrow views and not made the offer
April 11, 2014 -- Updated 1416 GMT (2216 HKT)
Al Awlaki
Almost three years after his death in a 2011 CIA drone strike in Yemen, Anwar al-Awlaki continues to inspire violent jihadist extremists in the U.S, writes Peter Bergen
April 12, 2014 -- Updated 0121 GMT (0921 HKT)
David Bianculli says Colbert is a smart, funny interviewer, but ditching his blowhard persona to take over the mainstream late-night role may cost him fans
April 10, 2014 -- Updated 1731 GMT (0131 HKT)
Rep. Paul Ryan says the Republican budget places its trust in the people, not in Washington
April 10, 2014 -- Updated 2128 GMT (0528 HKT)
Aaron David Miller says Obama isn't to blame for Kerry's lack of progress in resolving Mideast talks
April 14, 2014 -- Updated 1522 GMT (2322 HKT)
David Weinberger says beyond focusing on the horrors of the attack a year ago, it's worth remembering the lessons it taught about strength, the dangers of idle speculation and Boston's solidarity
April 10, 2014 -- Updated 1632 GMT (0032 HKT)
Katherine Newman says the motive for the school stabbing attack in Pennsylvania is not yet known, but research on such rampages turns up similarities in suspects and circumstances
April 11, 2014 -- Updated 1103 GMT (1903 HKT)
Simon Tisdall: Has John Kerry's recent track record left Russia's wily leader ever more convinced of U.S. weakness?
April 10, 2014 -- Updated 1640 GMT (0040 HKT)
Mel Robbins says Nate Scimio deserves credit for acting bravely in a frightening attack and shouldn't be criticized for posting a selfie afterward
April 9, 2014 -- Updated 1839 GMT (0239 HKT)
Wendy Townsend says the Rattlesnake Roundup -- where thousands of pounds of snakes are killed and tormented -- is barbaric
April 10, 2014 -- Updated 1345 GMT (2145 HKT)
Dr. Mary Mulcahy says doctors who tell their patients the truth risk getting bad ratings from them
April 9, 2014 -- Updated 1328 GMT (2128 HKT)
Peggy Drexler says the married Rep. McAllister, caught on video making out with a staffer, won't get a pass from voters who elected him as a Christian conservative with family values
April 9, 2014 -- Updated 1143 GMT (1943 HKT)
David Frum says the president has failed to react strongly to crises in Iran, Syria, Ukraine and Venezuela, encouraging others to act out
April 9, 2014 -- Updated 2057 GMT (0457 HKT)
Eric Liu says Paul Ryan gets it very wrong: The U.S.'s problem is not a culture of poverty, it is a culture of wealth that is destroying the American value linking work and reward
April 9, 2014 -- Updated 1151 GMT (1951 HKT)
Frida Ghitis writes: "We are still seeing the world mostly through men's eyes. We are still hearing it explained to us mostly by men."
April 10, 2014 -- Updated 1408 GMT (2208 HKT)
Chester Wisniewski says the Heartbleed bug shows how we're all tangled together, relying on each other for Internet security
April 9, 2014 -- Updated 1926 GMT (0326 HKT)
Danny Cevallos says an Ohio school that suspended a little kid for pointing his finger at another kid and pretending to shoot shows the growth in "zero tolerance" policies at school run amok
ADVERTISEMENT