Paris Sickened by terror no one imagined, free societies are suddenly wondering if they can afford their easygoing new world, with its open borders and liberties based on mutual trust.
A declaration of war by shadowy enemies has reordered priorities, presaging what are certain to be fundamental shifts.
"Daily life will be changed, the way we travel, the way we work, the way we look at each other," said Dominique Moisi, a French foreign affairs analyst, who put a sharp focus on the shock and anguish among Europeans.
Terrorists can only lose if nations unite against them, he said. But, he added: "They will win if they convert us from open, law-abiding societies into Fortress West. We can only survive by remaining what we are."
In the immediate aftermath of terrorism in America, European leaders lined up quickly behind the United States.
Former French Prime Minister Alain Juppe told a radio interviewer that European allies had to share a common burden with the United States, working together to suppress terrorism.
"Americans face a terrible dilemma," he said. "When they intervene in world affairs, they are reproached for imperialism. When they stand back, they are equally attacked. I wonder if we also don't have a responsibility here."
But in practice, tough joint action against suspected terrorists runs the risk of dampening individual rights and feeding the siege mentality that worries Moisi.
The immediate signs are unsettling.
Across a now seamless expanse of Western Europe, people nod in sympathy when they hear broadcast interviews with distraught Americans who say they would exchange personal freedoms for greater security.
"We can't go on as usual, that's obvious," restaurateur Rene Bourel said. "At any airport, so many workers move freely, cleaning planes, whatever. You think for 5,000 francs ($700) one wouldn't hide a knife by a seat?"
Loss of liberty
Human rights activists warn that experience shows special emergency powers do little more than restrict the liberties of ordinary people.
Maggie Beirne of the Committee for Administration of Justice in Northern Ireland has followed British attempts to quell terrorism since a 1972 decree suspended trial by jury and gave police exceptional powers.
"I sympathize with Americans," she said. "It's natural to want to hang (terrorists) and flog them. But emergency powers lead to abuse of power, fueling conflicts. The very response to terrorism actually feeds it."
France learned this the hard way. Forty years after a futile war to keep Algeria as a French state, military and police officials are now apologizing for torture used against suspected Arab terrorists.
At one stage, repression was so severe that some out-of-control security officers murdered Algerians in Paris and dumped their bodies into the Seine.
After the attacks Tuesday in the United States, France again applied part of a broad set of antiterrorism measures it calls "Vigipirate" to check identity papers and investigate suspicious activity, but ordered police to stay clearly within legal bounds.
Beyond constitutional abuses, there is a strong chance that the policies that have made life easier and business healthier will be sacrificed for security.
Charles Pasqua, who as France's interior minister pushed for tougher immigration laws, blames open borders for much of the problem. "You cannot keep out dangerous people when anyone can come into your country unchecked," said Pasqua, now a member of the European Parliament.
In recent years, much of the European Union has all but dissolved internal frontiers. Passports are checked on entry from outside the EU, but movement among member states is often as easy as going from New York to Connecticut.
Police still discreetly spot-check roads and ports, seeking suspicious profiles, but movement is essentially free, so terrorists can move people and explosives from place to place with hardly a care.
An entry stamp at Rome airport is a free pass to Brussels or Amsterdam. Any illegal who makes the harrowing voyage across the Straits of Gibraltar into Spain can catch a train to Berlin without having to produce a passport.
'New world order'
Much will depend on how quickly those responsible for the U.S. attacks are tracked down and punished, analysts say. Growing frustration might push people to accept drastic measures.
"It's classic: someone hurts you, you want to react," said Barry Goodfield, a San Francisco psychoanalyst and expert on conflict resolution. "I pray to God we have the sense to have sense."
Andre Lo Gallo, a former CIA counterintelligence chief, made a similar point. "This will take patience," he said. "They'll put everything aside until they find the right guys. But it won't be by close of business tomorrow."
Beyond uprooting clandestine networks, he added, Western governments must also work on the larger problems that lead to terrorism in the first place.
Moisi, in the end, is hopeful for "a new New World Order." The terror attack, like Pearl Harbor, showed Americans that they cannot avoid a leading role in world security, he said, and Europeans realize they must stand together with Washington.
"Hesitation in the Western world about cohesion and unity after the Cold War has ended," he said, "and we will emerge much stronger after Sept. 11, 2001."