WILL the rest of Europe join in? Can what the French call their ``alliance within the alliance'' with West Germany become the core of a pan-European defense, as both President Francois Mitterrand and Prime Minister Jacques Chirac hope? The answer depends primarily on the ``strong man'' of Europe, Prime Minister Margaret Thatcher, and on how far she carries Britain's newfound acceptance of European identity into the domain of conventional and nuclear security. It depends further on Italy's demonstrated desire to play a political role commensurate with its newfound economic muscle. And it depends further still on how the smaller countries also take part in collaborative weapons procurement and in the jerky process of ``revitalizing'' the Western European Union (WEU), the seven-nation pact on collective security, comprising the four large European states and the Benelux countries and dating back to 1954.
Jean Picq, a defense policy adviser to Mr. Chirac, presents a strong case for a unified European voice that could be ``clear'' on a ``European conception of security.'' Such a development, he says, would be ``the beginning of the comeback of Europe for Europe.'' And it would, he says, increase the chances that Europe will be listened to.
In the ``post-Reykjavik'' world, he suggests, if Europe ``doesn't weigh in on this [security issue], it won't exist anymore.''
The British Foreign Office has somewhat the same view, though being British, it is less interested in French-style declarations of principle than in practical measures of coordination.
Mrs. Thatcher, by all accounts, while jolted by the American disregard of Europe at the superpower summit in Reykjavik, Iceland, last October, is still less troubled than her ministries; she tends to put less store in a European ``alliance within the alliance'' than in the rest of the Anglo-American special relationship and her own ability to persuade President Reagan to alter vexing policies.
In the conventional field, the British have some impatience with the apparent inconsistency between French rhetoric about European solidarity and continued French aloofness from NATO. One official in London, while welcoming France's increasing engagement, suggested dryly that daily cooperation between the British Army on the Rhine and West German forces far surpasses the occasional ballyhooed French-West German maneuver.
Thatcher has recently made a point of consulting the French on East-West issues, however; she conspicuously visited both Paris and Bonn before her trip to Moscow this year. And there is an obvious rapprochement of bilateral British and French interests in the nuclear arena.
Whatever the considerable differences in their nuclear doctrines and planning, the two countries have a common desire to protect the effectiveness of their own arsenals both against any double regime of antimissile defense (``star wars'') and against the cuts in purely European capability that Moscow repeatedly tries to extract from superpower arms control negotiations. The projected sixfold or more proliferation of British and French warheads in the next decade will make these questions especially acute in a period when the superpowers will presumably be pruning their much larger nuclear inventories.
One idea that some European strategists are toying with - others reject it summarily - is coordinating French and British nuclear deterrence with sufficient ambiguity for Moscow to think that the two may be extending this deterrence to cover West Germany as a kind of ``reinsurance'' to the American nuclear guarantee.
Britain's nuclear force is, of course, already committed to NATO, and therefore to West Germany, in most circumstances. The real question mark for any ``extended deterrence'' is therefore France. And a major question for London in nuclear cooperation is how far Paris might be ready to adjust its nuclear doctrine of one all-out spasm to NATO's doctrine of graduated escalation.
A few strategists in and outside France speak of some ``convergence'' already, and France did agree last month to receive some nuclear information from NATO for the first time in decades. Full convergence is still a long way off, however; in circular logic, any French moves toward NATO doctrine at this point are perhaps best measured in whatever British-French cooperation develops.
CERTAINLY both right and left mainstreams in Paris welcome in private the prospect of increased bilateral nuclear coordination. And British and French officials note that bilateral contacts have long since established mutual landing rights of nuclear carriers in emergencies and lately have discussed tentatively the possibilities of joint submarine maintenance, coordinated submarine sailing schedules, and perhaps even interchangeability of missiles between the two countries' submarines. Any cooperative targeting is a much more sensitive question.
Sir James Eberle of London's Royal Institute of International Affairs thinks that the ``sheer requirements of size [for nuclear deterrence] to be minimally credible in the 21st century'' in an environment of some strategic defense will compel ``Britain and France to get their heads together and think what the next systems after the present ones should be.'' He also believes that ``Britain and France will be forced to de facto extended deterrence.''
Dominique David of the Foundation for National Defense Studies, in Paris, also envisages a situation in which ``France does not cover Germany officially, but where the Soviets may not intervene in Germany without asking if the French will respond. The basis of credibility in the Federal Republic of [West] Germany is that the Soviet Union cannot be sure that France will not respond with nuclear arms to defend West Germany.''
Along the same lines, defense adviser Picq argues that the proper question is not extending a French nuclear guarantee to West Germany, but rather ``establishing a situation where adversaries see a common destiny of these countries so that this has the same effect'' as extended deterrence.
In the conventional area, if there is a move toward greater political-military coordination in Europe, the likely channels for it are intensified bilateral contacts, the Independent European Program Group (IEPG), and the WEU. For years the WEU languished, until the French resurrected it in the 1980s as a standing, convenient, non-NATO forum that France belongs to, that is strictly European, and that moreover comprises only Europeans who are, as one British diplomat put it, ``serious'' about defense.
The French temporarily lost interest in the WEU once the West Germans actually deployed NATO missiles in 1983 and French worry about potential German neutralism subsided.
The Reykjavik summit and the Euromissile arms control negotiations rekindled French fears about the Germans, however, and added new fears about the decline of Mr. Reagan and the seductive attractiveness of Soviet leader Mikhail Gorbachev. Chirac is therefore now campaigning to crown the WEU's two-year ``revitalization'' this fall with a new ``charter.''
The WEU's sister organization, for European cooperation in weapons procurement, is the decade-old IEPG. The record of multilateral and bilateral efforts so far is spotty, with some expensive successes like the Tornado fighter aircraft, and some busts like the French-German tank.
The multilateral European fighter, the biggest project for the 1990s, is proceeding without French participation, not for lack of French government enthusiasm, but because of the refusal of the Dessault corporation to compromise on its share.
The trend shows a gradual increase in collaborative production. West Germany, Britain, and Italy are involved in most projects, and Britain now spends 15 percent of its equipment budget on collaborative programs.
Whatever the chosen forums, there is clearly more incentive for the Europeans to hang together in security now than at any time since France vetoed the European Defense Community in 1954. The motor of a sense of crisis in the West German elite about gathering American disengagement and in the French elite about America and West Germany propels both Bonn and Paris in this direction.
The British elite, although not feeling the same degree of urgency, does not want to and will not be left behind, nor will Italy. And a Dutch official expressed the sentiment of several of the smaller countries in saying recently that his nation, too, would like to contribute troops to any joint French-West German brigade.
A West German general comments, ``I think there is a spreading feeling in France as in Germany that we have to succeed or we will perish.'' About Britain he is not yet sure.