The United States will increasingly turn to precision airstrikes to counter the threat from radical Islam as it shrinks its military presence in Afghanistan and Iraq.
"This administration has made a very conscious decision that it wants to get out of large conventional-warfare solutions and wants to emphasize counterterrorism and a lighter footprint on the ground," said Bruce Riedel, a former CIA official.
On Friday, a U.S. airstrike in Yemen killed Anwar al-Awlaki, an anti-American cleric who was behind several high-profile attempted attacks on the United States. His rhetoric also helped inspire Maj. Nidal Hasan, an Army psychiatrist who is charged with killing 13 people during a shooting rampage at Fort Hood, a military base in Texas.
Friday's strike in Yemen was the latest in a growing U.S. reliance on airstrikes to target al-Qaeda and its affiliates throughout the region.
The drone strikes allow the U.S. to target militants far and wide, reflecting the growing dispersal of al-Qaeda and its affiliates. The United States has targeted militants in Pakistan, Somalia and Yemen with drone strikes in recent years.
"This is clearly the weapon of choice when it comes to military action against al-Qaeda," said Rick Nelson, an analyst at the Center for Strategic and International Studies.
The increase in drone strikes comes as the United States is reducing its military presence in Afghanistan and Iraq, wars that were costly in American lives and money.
Drone strikes are seen as far less expensive and less likely to risk American lives. "We no longer have the political or economic resources" to conduct large operations such as those in Afghanistan and Iraq, Nelson said.
The U.S. strategy also includes establishing ties with regional governments in order to get intelligence that can pinpoint the location of militants or to assist in targeting them with raids. And it helps to have approval from a friendly government before launching strikes within its borders.
"The model is to combine long-distance remote strikes on key planners and leaders (and) build up local governments to control their own space," said Peter Singer, director of the 21st Century Defense Initiative at the Brookings Institution.
President Obama praised Yemen's cooperation with the United States when he announced the death of al-Awlaki.
But the U.S.-Yemen relationship has been complicated by a widening revolt against Yemen's President Ali Abdullah Saleh, who only recently returned to the country after being wounded in an attack on the presidential compound.
Growing violence there has threatened Saleh's regime and placed the United States in the position of working with a regime that may collapse, leaving uncertainty in its wake.
Riedel said Saudi Arabia, another key U.S. partner in the region, also may have supplied intelligence that helped target al-Awlaki. He was killed in Aljawf, a region near the Saudi border.
Airstrikes carry the risk of killing innocent civilians, which helps turn people against the United States and places internal pressure on friendly regimes that allow the strikes.
"The drones are a double-edged sword," Riedel said. "It really doesn't matter how clean the strikes are. … It is very hard for us to persuade Yemenis or Pakistanis that only bad guys get killed.
"We don't have a whole lot of credibility in Yemen and Pakistan, and they tend to believe the worst," he said.
The drone strikes recall previous and less successful cruise missiles strikes, such as 1998 missile attacks in Sudan and Afghanistan. The strikes were launched in retaliation for attacks on U.S. embassies in Tanzania and Kenya.
The U.S. cruise missile strikes were aimed at a factory in Sudan, which the United States said was making chemicals to help Osama bin Laden, who planned the embassy attacks, and at a training camp in Afghanistan. Bin Laden was not at the Afghanistan camp when the missiles struck, and there were questions raised about the role of the chemical factory.
Today's strikes are based on better on-the-ground intelligence and more precise technology, analysts say.
"Drones are more effective than cruise missiles," said Richard Fontaine, a military analyst at the Center for a New American Security.