Al Qaeda may have a new twist in its strategy: bomb attacks designed to blow up alliances as well as buildings.
Thursday's sobering truck explosions in Istanbul were but the latest in a series of strikes aimed at US allies in the war on terror.
This doesn't mean Washington is certain Al Qaeda is behind all the latest violence. It's possible that Iraqi insurgents sneaked across the border and carried out Thursday's Istanbul attacks.
Nor might cleaving allies away from the US be Al Qaeda's only goal. Osama bin Laden has long excoriated the leaders of Muslim nations that he deems to have wandered from the true faith.
But the recent bombs bear traces of known Al Qaeda tradecraft. There is a pattern emerging, say some experts, that indicates the terror group is determined to wage a sort of world war.
"This feels like a strategic shift to me, or a phase shift," says Jerrold Post, a former CIA official who heads the political psychology program at George Washington University.
If Al Qaeda is behind Thursday's attacks - as well as last week's twin bombings of Istanbul synagogues and the explosions that devastated a residential compound in Riyadh, Saudi Arabia, earlier this month - it would mark an unprecedented surge in activity for the Islamist terrorists.
Many more people were killed on September 11, 2001, and in Al Qaeda attacks in Bali, but the ability to carry out the recent series of obviously related attacks is itself impressive, say analysts.
That's one reason to lend credence to Al Qaeda claims of culpability. The showiness of the attacks, so close together, is one of their trademarks.
"Many terrorist groups wish they could do this but if you look at the historical record, relatively few have the capabilities - intelligence, reconnaissance, dedication, the loyalty of their cadres," says Bruce Hoffman, an expert on terrorism at the RAND Corp.
Another indication that it is in fact Al Qaeda that is on the march is the targets. Al Qaeda likes to strike in new, unsuspecting locations, against lightly defended buildings or compounds. Who would have thought that housing for foreign Arab workers would be attacked, as happened in Saudi Arabia? A British bank in Istanbul might have thought itself obscure enough to be safe.
Al Qaeda planners are also "success freaks," in a phrase used by Mr. Hoffman. The attacks themselves are meticulous. If the terrorists wanted to frighten Britain, they might have attacked in Britain itself. But the heavy security there would have lowered chances for pulling the attack off.
Turkey, on the other hand, is a geographical crossroads. It's a member of NATO. It's close to Iraq. Al Qaeda leaders would surely see a successful act of terrorism there as something that would send a number of powerful messages.
"Of course it's designed to sow doubt and discord in America's allies," says Mr. Hoffman. "They can become grievous sufferers, as Turkey has, whether by supporting US policies and cooperating in the war on terrorism or being a member of the West."
The timing of Thursday's attacks, coming during President Bush's high-profile visit to the British Isles, is obviously a jab at Prime MInister Tony Blair and his staunch support of Bush policies. Whether the bombs will have the effect in Britain that Al Qaeda would want is less clear.
The war in Iraq won't suddenly become more popular in London. But protests against Bush's visit were suddenly pushed off the nation's front pages, replaced by pictures of shocked and wounded victims of attacks against British targets.
But the attacks did not occur in Britain itself, and the British are famously impervious to intimidation. "I'm not sure this will have any significant impact on Britain," says Daniel Benjamin, an expert on terrorism and the Middle East at the Center for Strategic and International Studies.
The impact on Turkey itself could be severe, judges Benjamin, insofar as it increases insecurity and panic in a nation that has been relatively isolated from much of the violence that has affected the rest of its region.
Such a reaction could complicate US relations with other Muslim nations, given that Washington often points to Turkey as a model of democracy and separation of religion and state for a majority Muslim land.
The nature of the Turkish attacks - two multiple-pronged operations carried out in a short period of time - is just the kind of thing counterterrorism experts have worried about for some time.
"That is hugely damaging for the Turks, and for people everywhere, I think," says Daniel Benjamin of CSIS, who is also the co-author of "The Sacred Age of Terror." "If they can do it there, they can do it elsewhere."
But sowing fear and discord among the nations arrayed against it is likely only one of Al Qaeda's strategic aims.
Given the drama and deadliness of the Sept. 11 attacks, it is easy to forget that Al Qaeda's first target was not the West but other Muslims.
Some of the strongest language in the early communiqués of Osama bin Laden and his associates was directed at Hosni Mubarak of Egypt, the ruling family in Saudi Arabia, and even Ataturk, founder of the modern Turkish state. Their crime, in Al Qaeda's eyes: attempting to modernize and in some cases secularize their states.
Thus bin Laden talked about the need to restore the caliphate in Turkey, and remake authentic Muslim states governed by Islamic law.
"It's important to remember that actually, the US is not the primary target," says Jerrold Post of George Washington University. "The primary target, if you go back to a lot of the earlier writings of bin Laden and [associates], was these apostate regimes."
Attacking the US was itself something of a strategic, phased shift of strategy, judges Post. Egypt and Saudi Arabia might in some way have even been a little relieved to see bin Laden turn his ire on a more distant, more powerful nation, he says.
For strategic reasons, bin Laden had decided to go after targets that were far. Now he may have shifted back to targets that are near - or at least, nearer to his base of support.
"I see this as reflecting a threat to all Muslim states and leaderships," says Dr. Post.