Charles Powell: Isolation will no longer be an option for America

Last week's atrocities in New York and Washington will necessitate a far-reaching reorientation of diplomacy. Since the end of the Cold War and the demise of the Soviet Union, the institutions of the Western democracies have lacked the binding force of a common enemy.

The terrorism we witnessed last week is a form of asymmetric warfare – it uses fairly primitive methods of war-making to wreak damage on technologically advanced societies. Overcoming terrorism will surely now become one of the central tasks of diplomacy, backed by effective intelligence and military power equipped to deal with this sort of threat rather than conventional warfare.

The first effect has been to reinforce Western solidarity and the traditional institution of the Atlantic alliance, above all Nato. Nato members have come together with speed to support the US and, for the first time, invoke article 5 of the Nato treaty: the provision that an attack on one is an attack on all. After a decade in which Nato has seemed to lose relevance while the focus has shifted to exclusively European institutions, the two sides of the Atlantic looked like drifting apart. Now Nato returns to centre stage.

More remarkable still is the speed with which Russia has moved to align itself with Nato. Moscow may have its own motives in relation to Chechnya and the Islamic countries around its southern borders but that does not make its support less valuable. It signifies a shift in relations between the major powers which may lead to a new pattern of co-operation. It remains to be seen whether China will join this coalition. It too faces problems with Islamic groups within its borders and has a strong incentive to see terrorism defeated.

I do not believe that recent terrible events will drive the US to isolation, as some predict. The lesson is surely that the US has to be even more engaged in the world in order to defend itself.

As well as stiff punishment of terrorists and the governments that sustain and abet them, the US needs to address the causes of terrorism. This means, above all, a more energetic effort to resolve the problems behind Israel and the Palestinians. Washington has to balance retributive action with constructive solutions to the despair that motivates terrorism and the obscenity of suicide bombers.

Within Britain these events should strengthen the hand of Atlanticists against those who question the value of the special relationship with the US. That should encourage the Government to recalibrate its diplomacy to give greater weight to the Atlantic relationship and to encourage Europe to think about ways to strengthen that relationship. The right way to meet a common threat is by drawing together, not by demonstrating Europe's separate identity.

Lord Powell of Bayswater was foreign affairs adviser to Margaret Thatcher