First came the closing of U.S. embassies and consulates throughout the Middle East and North Africa this week, along with a worldwide travel alert warning of a possible al Qaeda attack in the region.
In addition, Americans were told to leave Yemen, the epicenter of al Qaeda militancy in the Middle East, and the State Department pulled out non-emergency embassy personnel on military aircraft that flew them to Germany.
U.S. forces in the region were put on two-hour alert for mission readiness, and now there have been seven suspected U.S. drone strikes in Yemen, where the local al Qaeda leader is now believed to be the terror group's global second-in-command.
The seriousness of the U.S. response indicated that al Qaeda was not as decimated and on-the-run as President Barack Obama's administration has claimed for some time, including in last year's presidential campaign.
Critics, including a miffed Yemeni government, quickly said the U.S. adoption of such a defensive posture only bolstered the bad guys, giving al Qaeda a propaganda victory.
However, security analysts noted a strategic underpinning to the very public defensive posture that generated headlines around the world.
Closing diplomatic facilities that could be targeted can disrupt the planning of the attackers, creating an opening to go after them, noted CNN National Security Contributor Frances Fragos Townsend.
"Once you take targets away, it buys you additional time to try and disrupt, to identify the cell, the operators in country and the region, and work with your partners in the region to try and ... get them in custody or disrupt the plot," said Townsend, a former homeland security adviser in the Bush administration. "So, some of this operationally is about buying time."
Stepped up drone strikes
The intensifying drone strikes against militants in Yemen may be one result.
Seven reported in the past two weeks have killed at least 31 people, according to a tally by Yemeni officials.
The latest occurred on Thursday, including one in Mareb province in central Yemen that targeted two vehicles and killed four people with links to al Qaeda, along with two civilians, local security officials said.
Al Qaeda in the Arabian Peninsula, the terror group's Yemeni affiliate, shot down a Yemeni military helicopter in the province on Tuesday, according to a government official said. However, Yemeni officials note that no high-value targets have been hit by the drone strikes so far.
The leader of AQAP, Nasir al-Wuhayshi, was recently appointed by al Qaeda leader Ayman al-Zawahiri as his top deputy, U.S. intelligence officials believe.
A recently intercepted message from al-Zawahiri to al-Wuhayshi telling AQAP to "do something" set off the embassy closings by the United States, Britain and some other countries.
What intelligence officials still don't know includes the specifics of any al Qaeda plot and exactly how al-Zawahiri -- believed to be somewhere in the mountainous border region between Afghanistan and Pakistan -- communicates with al-Wuhayshi and other top operatives.
Other intel info
CNN Pentagon Correspondent Barbara Starr reported that other steps by the U.S. intelligence community includes scouring National Security Agency intercepts; studying imagery from drones as satellites, as well as websites, chat rooms and webhosting services; looking at financial transactions and other connections of known operatives, and talking to known couriers and others on the ground.
Obama touched on the latest threats during a speech on Wednesday to military forces at Camp Pendleton in California, where he heralded the U.S. successes in taking out Osama bin Laden and putting what he called "the core of al Qaeda" in Afghanistan and Pakistan "on the way to defeat."
"Even as we decimated the al Qaeda leadership that attacked us on 9/11, al Qaeda affiliates and like-minded extremists still threaten our homeland," Obama said. "They still threaten our diplomatic facilities. They still threaten our businesses abroad. And we have got to take these threats seriously, and do all we can to confront them. We have been reminded of this again in recent days."
Some are questioning the U.S. response, with veteran journalist Ted Koppel writing in the Wall Street Journal on Tuesday that al Qaeda is getting exactly what it wants in the embassy closings and other actions taken.
Terrorism, Koppel wrote, "is the means by which the weak induce the powerful to inflict damage upon themselves -- and al Qaeda and groups like it are surely counting on that as the centerpiece of their strategy."
"It appears to be working," he continued, noting the closing of diplomatic facilities and drone strikes.
"We have created an economy of fear, an industry of fear, a national psychology of fear," Koppel concluded. "Al Qaeda could never have achieved that on its own. We have inflicted it on ourselves."
Taking threat seriously
Yemen's government also criticized the United States, saying that closing diplomatic facilities and withdrawing staff "serves the interests of the extremists and undermines the exceptional cooperation between Yemen and the international alliance against terrorism."
However, former U.S. Homeland Security Secretary Michael Chertoff told CNN on Wednesday that the administration had little choice in mounting a potent defense against the perceived threat.
"I respect Ted Koppel as a journalist, but he never had the responsibility of having American lives on his shoulders," Chertoff said. "And I think you have to understand that when you're a president or a senior leader in the government and you have that responsibility, there's a different lens that you use."
The experiences of dealing with terrorism in past decades, including the Boston Marathon bombing in April, had brought authorities to "a place where people do take the threat seriously, but are not getting hysterical," Chertoff said.
To CNN Law Enforcement Analyst Tom Fuentes, the U.S. response to the al Qaeda threat could provide a propaganda boost by sending a message that the group "is so powerful and so pervasive all over the world that they could do this to us anywhere, any time."
"When you see TV images of tanks in front of U.S. embassies, because al Qaeda said we might do something to you, somewhere, some time, I know the concern of wanting to protect the facility, but on the other hand, those images being displayed worldwide do play into their hands," said Fuentes, a former FBI assistant director.
Chertoff agreed that closing U.S. embassies and consulates might have been a mistake, noting that security could have been increased without the symbolic step of shutting the doors.
"It's the same problem we had back in the day of the color code," he said, referring to the Bush administration system of security alerts. "It's easier to go up to orange than it is to come down from orange. They may have boxed themselves in a little bit with respect to the actual closures."
A new generation
At the same time, Chertoff noted that militant groups such as al Qaeda now have a new generation of battle-hardened fighters from wars in Iraq and Syria, as well as enhanced bomb-making techniques.
Attackers may lack the resources and scale to pull off another 9/11-style mission, but they are better poised for smaller attacks on U.S. and Western targets in many places.
Fuentes agreed, saying the terrorists "have gradually over time shifted to realizing that the American people will not tolerate even one or two people being killed, much less 3,000."
Bruce Riedel of the Brookings Institution said most of the focus of al Qaeda and al-Zawahari was on post-Arab Spring crises such as Egypt's political limbo. He noted that al-Zawahiri recently reminded Egyptian Islamists loyal to the Muslim Brotherhood of ousted President Mohamed Morsy that al Qaeda always said the path to power was through jihad and not the ballot box.
"The new generation of al Qaeda---AQ 3.0, if you like---is more focused on the nearby enemy close to home than the faraway enemy in America and Europe. For now at least," Riedel wrote in an opinion piece this week on The Daily Beast website.
"But easy targets like the natural gas plant in Algeria attacked last winter by an al Qaeda cell based in Libya and Mali allow local groups to kill dozens of foreign 'crusaders.' And embassies are always favorite targets. After all, that is how al Qaeda started 15 years ago this month when it blew up our missions in Kenya and Tanzania."
Condemnation from Nobel laureate
In Yemen, many of AQAP's operatives, including its leadership, have retreated into remote areas to regroup after a military offensive against them last year.
Yemeni security forces have over the past 18 months recaptured swathes of territory that were briefly held by AQAP, particularly in the south.
AQAP has not mounted a large-scale suicide attack on Yemen's security forces since May 2012, when more than 100 soldiers were killed by a suicide bomber as they trained for a parade in Sanaa, the capital. In July, a bomb killed several soldiers there.
Now the U.S. drone strikes have stoked anger, with the country's Nobel peace laureate, Tawakkol Karman, condemning the latest attack.
"The killing conducted by unmanned planes in Yemen is outside the law and worse than the terrorist activities of individuals and groups," she said, adding that the drone strikes were "degrading" to Yemenis and violate their human rights.
CNN's Laura Smith-Spark, Hakim Almasmari, Mohammed Jamjoom and Ben Brumfield contributed to this report.