The targets so far have been British and Jewish, but the next major victim of the deadly bombings jolting this nation that straddles two continents may be the delicate political balance of its Islamic-led government.
Struggling to prove itself democratic and moderate, Turkey's government, which is led by an Islamic party, suddenly finds itself compelled to battle Islamic bombers. To do that effectively without alienating a core constituency while keeping a restive, secular Turkish army at bay is likely to prove a formidable task for Prime Minister Recep Tayyip Erdogan.
The nature of Turkey's evolving identity may be at stake. As the sole Muslim member of the North Atlantic Treaty Organization is pulling itself out of a long economic decline and marching steadily toward Western-style democracy, it has been hit with the deadliest spasm of violence in decades. Its embrace of the West, experts say, is part of what has made Turkey a target -- its destabilization is the attackers' goal.
"Turkey's grand experiment, where an Islamic party is trying to redefine itself as a conservative democratic one, is now under threat," said Bulent Aliriza, head of the Turkey Project at the Center for Strategic and International Studies in Washington.
Erdogan has defined it this way: If he and his party could show that Islam and democracy were compatible, he said in a major speech last year, a clash of civilizations was avoidable.
Now Erdogan must demonstrate to a skeptical world that he is willing and able to combat Islamic militancy. Doing so without reverting to Turkey's previously harsh tactics against dissent would require a new and perhaps even more delicate balancing act.
Inevitably, he must enlist the military, with which relations are strained and whose power he was in the process of curtailing. Yet a broad crackdown could play into the hands of the extremists who blew up two synagogues, the British Consulate and the offices of one of the world's largest banks, all within five days.
Failure to act decisively also poses risks for the government's stability. Thus far, Erdogan has pledged to pursue and strike "like a fist" those responsible for the attacks. The bombings Thursday killed at least 32 people and occurred in the middle of the holy month of Ramadan. "Those who bloodied this holy day and massacred innocent people will account for it in both worlds," Erdogan said. "They will be damned until eternity."
Eager to be accepted into the European Union, Turkey's government for the last year has taken major steps to bring its civil rights, political structures and military in line with EU standards.
This has meant, on paper at least, substantial oversight of military power and the granting of cultural rights to the nation's long-repressed Kurdish minority, including permission to broadcast in the Kurdish language. Just this month, the government drafted a bill that would require openness from a top military advisory council that wields enormous influence.
These reforms have not sat well with the army, an overweening presence that sees itself as the guarantor of Turkey's secular system and is unaccustomed to having its wings clipped.
Mistrust of Erdogan's party, elected in a landslide last year, runs deep among the generals and colonels, and they might be looking for an opening to slap down the civilians in charge.
Gen. Ilker Basbug, the Turkish army's deputy chief of staff, emerged from a meeting with U.S. Deputy Defense Secretary Paul D. Wolfowitz in Washington on Thursday and suggested that the bombings might have been intended to provoke a "wrong" military reaction. Basbug said the military was not planning a coup. The fact that he raised the prospect, unprompted, made some people nervous.
"We will not go this way," he said. "We will overcome these difficulties within a normal way."
Already, there have been scattered, street-level rumblings that martial law might be necessary to restore security. Some Turks questioned the government's decision to release 130 members of the Turkish Hezbollah, a militant Islamic group, in September under a 4-month-old amnesty.
Others suggested that security was lax, especially in cosmopolitan Istanbul. The Milliyet newspaper reported Friday that one of its reporters was able to buy 35 items to manufacture eight bombs from a city shopping district for the equivalent of $40 and with no questions asked.
But experts believe that the army, which has unseated four elected governments in four decades, most recently in 1997, is still a long way from moving to overthrow Erdogan.
First, his Justice and Development Party holds a two-thirds majority in parliament; the army has always been keen to heed public opinion. Second, the military arguably could be held accountable for failing to preempt terrorist plans, as could the civilian security services.
"There have always been ups and downs in military-government relations, especially over how to handle the Islamic groups, but the current government has shown a real determination" to control radicals, said Lale Sariibrahimoglu, a military affairs expert based in Ankara, the capital. "So for now, I don't think the army will blame the government at a time when what we need is solidarity."
At the very least, however, the army could use the surge in violence as a pretext for reversing or freezing EU-backed reforms.
British Foreign Secretary Jack Straw, who rushed to Istanbul after one of the bombings claimed the life of Britain's top representative here, reiterated the importance of Turkey's joining the EU. The government is led by a single party for the first time in a decade, giving Erdogan much greater freedom and political muscle to push forward an agenda, at least until now.
"I fear that ... groups like the military will use this to set back the reform process, saying Turkey is not ready for democracy, and use this as an excuse to revert to suppression of freedoms," said a European diplomat.
If the army were to launch an overly zealous crackdown, there's no telling where it would end. Its repressive measures during decades of war with Kurdish guerrillas was notorious. Similarly, its treatment of Islamists has at times been severe -- and has targeted those who now rule.
Erdogan, a devout Muslim, was convicted in 1998 of inciting religious violence, jailed and banned from holding public office. After his revamped and renamed political party won election last year, the government amended the constitution to allow him to run for office. Early this year, as head of the party, he took over as prime minister.
Burnishing his own democratic credentials and proving that his own firebrand Islamist past is indeed past are important goals for Erdogan. Many Turks and foreign diplomats have doubts, however, and have long been suspicious that he harbors fundamentalist beliefs and intentions.
The celebration last month of the 80th anniversary of Turkey's founding as a secular republic, built from the ruins of the Ottoman Empire, became an imbroglio over the use of headscarves by pious Muslim women. President Ahmet Necdet Sezer refused to invite the scarf-wearing wives of lawmakers and other top officials to his annual Republic Day reception. Erdogan's wife was among the outcasts.
Perhaps the government believed that it was somewhat sheltered from Islamic terrorism because of its roots. If so, it was a deadly miscalculation. On Friday, government officials were eager to distance their interpretations of Islam from that of the suicide bombers.
Officials said suspects had been quickly identified and their accomplices were being pursued.
Faruk Demir, head of the Higher Strategy Center think tank in Ankara, said the association of Islam and terrorism had put enormous pressure on the government, which was caught between toeing the anti-terrorism line that pleases Washington and the West and not repelling domestic religious conservatives.
"It's a double-edged sword," he said. "The government will need to strike a balance, one that reflects Turkey's own brand of moderate Islam that distinguishes it from the rest of the Islamic world."
Special correspondent Amberin Zaman contributed to this report.