It's a pattern that governments fighting Islamic extremism don't want to see repeated -- success cracking down on militants in one country boosts terrorism elsewhere.
In Afghanistan, for example, the U.S. invasion prompted al Qaeda's leadership to seek shelter in the tribal areas of Pakistan, beyond the reach of the central government in Islamabad.
Similarly, experts say al Qaeda in the Arab Peninsula, the group that claimed responsibility for the attempted bombing of a Detroit-bound flight on Dec. 25, was formed in Yemen partly because of Saudi Arabia's success at abolishing militant groups next door.
Saudi authorities have been waging a campaign to rehabilitate, imprison or kill suspected extremists since a wave of terrorist attacks wracked the country in 2003 and 2004. But some militants fled south to Yemen, where AQAP was created last January.
"There was a balloon effect," said Letta Tayler, a terrorism and counterterrorism researcher with Human Rights Watch. "It's a much more hospitable environment for al Qaeda than Saudi Arabia was following the crackdown."
The American military had been helping Yemen combat al Qaeda before Umar Farouq Abdulmutallab, a 23-year-old Nigerian who had taken Arabic classes in Yemen, allegedly tried to detonate a bomb on board Flight 253.
Earlier in December, the U.S. military assisted with two air strikes on Yemeni territory. They were reportedly aimed at suspected al Qaeda leaders and killed several dozen civilians. The second strike took place a day before Abdulmutallab boarded a flight to Detroit.
The U.S. also provided nearly US$70 million in military aid to Yemen in 2009. Gen. David H. Petraeus, the head of U.S. Central Command, has said the Department of Defense will double that amount this year.
Meanwhile, British Prime Minister Gordon Brown announced that his government, along with the U.S., will help Yemen fund a new counterterorrism force.
Later this month, the British capital will also host two simultaneous international conferences, one on Afghanistan and the other on Yemen.
Tayler said that countries seeking to combat radicalization in Yemen would do well to learn from U.S. General Stanley McChrystal, NATO's top commander in Afghanistan.
To defeat the Taliban and keep al Qaeda from returning to Kabul, McChrystal has recommended that U.S. troops use "courageous restraint."
"At the end of the day, the success of this operation will be determined in the minds of the Afghan people," McChrystal said last month. "It's not the number of people you kill. It's the number of people you convince. It's the number of people that don't get killed. It's the number of houses that aren't destroyed."
As with Afghanistan, experts say there's no easy solution to countering al Qaeda in Yemen.
Joost Hiltermann, deputy program director with International Crisis Group's Middle East and North Africa arm, warned that military intervention could weaken the central government, allowing al Qaeda more free rein there.
"In a situation as fragile as in Yemen, to put a major external military force could be fatal," Hiltermann told CTV.ca. "The country may not be able to sustain it."
Complex problems
Yemen is a semi-mountainous country on the southern tip of the Arabian peninsula with a fast-growing population of some 22 million people.
One of the least developed countries outside sub-Saharan Africa, the UN Human Development Index estimates that 35 per cent of Yemenis live in poverty. Malnourishment is a common affliction for children and nearly half the population is illiterate.
Oil, which brings in three-quarters of the national income, is running out. Tourism was touted as a possible alternative revenue generator (Yemen houses four UNESCO heritage sites). But visitor numbers have dropped due to attacks on foreigners, and political instability.
About 150,000 people have been displaced by a civil war that has been raging intermittently near Saada, in the north of the country, since 2004. The Yemeni government has been accused of indiscriminate bombing in the conflict, which Hiltermann says "is clearly escalating."
In the south, a secessionist movement flared up last spring, bringing hundreds of thousands of protesters into the streets.
"The bottom line is, the country's in chaos," Tayler said. "There are no prospects for youth and most citizens are concerned about how to get the next meal."
As Yemen's troubles mount, President Ali Abdullah Saleh's government is losing more control. His reach, which doesn't extend to many parts of the country, is weakening further.
Marisa L. Porges, an international affairs fellow at the Council on Foreign Relations who advises on counterterrorism for the U.S. Department of Defense, travelled to Yemen in the fall.
"There are so many domestic problems that al Qaeda isn't a top priority," Porges said by phone from Washington.
"In private conversations, many officials say 'we're already there -- the state has failed.'" she added. "This is the pervading sense now."
Confronting al Qaeda
AQAP launched several attacks last year, including an attempt to assassinate Saudi Arabia's counterterrorism chief, Prince Mohammed bin Nayef, and two attacks against South Korean tourists and dignitaries -- all using suicide bombers.
But the attempted Dec. 25 airliner attack seems to represent the group's first plot against a target outside the region.
While that incident focused the international community's attention on AQAP, experts say it will be hard if not impossible to keep such groups off Yemeni territory without addressing the country's other problems.
Jane Novak, an American analyst and expert on Yemen, warned that President Saleh may simply use military aid from the U.S. to oppress his opponents, while the country goes down.
"It's such a complex situation," she said. "It's very difficult in Yemen to find anyone there to work with."
Convincing Saleh, who has ruled the country for three decades, to implement political reforms could help make the country less hospitable for terrorist groups by boosting loyalty to the government, Novak said.
"Basically in Yemen they consider (the Saleh regime) a tyranny, and an incompetent one as well," she said. "To reduce the instability, the ungoverned regions, they need to somehow force power-sharing and the respect for civil rights."
Tayler echoed that view, saying policies that reduce oppression and boost faith in the government are needed to fight al Qaeda there effectively.
"You need a holistic approach," Tayler said. "Otherwise, the counterterrorism policy will simply backfire -- whether it's Pakistan, whether it's Yemen, whether it's Afghanistan."
