United States of Europe?

IS Britain part of Europe? Well, yes and no. Britain is certainly not part of Africa or Asia, but over the years it has kept its distance from the Continent, that is, the European one. And now British Prime Minister Margaret Thatcher has put some distance between her country and much of the rest of the European Community. Enthusiasm for efforts to integrate Europe economically - to create a ``single market'' by 1992 - is in the air.

But Mrs. Thatcher has publicly attacked Jacques Delors, EC Commission president, for what she calls his ``airy fairy'' and ``absurd'' ideas about a Community-wide central bank and Eurocurrency. Moreover, Mr. Delors's recent prediction that within 10 years, 80 percent of social and economic decisions will be made at the Community, rather than the national, level did not sit well with Thatcher, who has very definite ideas about national sovereignty.

She has favored economic integration, but in the sense of deregulation, not of policy coordination.

Progress toward ``1992'' has gone faster than many Euroskeptics expected; February's agreement on agricultural subsidies, for instance, showed that the 12 really can face a tough issue and deal with it. But much work lies ahead. For all the recent enthusiasm about entrepreneurial spirit and the free market, the protectionist orientation is dying hard.

The major concern is whether unified Europe will really be a truly open, convenient, single market or a cartel - Fortress Europe. Surely freer trade is preferable to protectionism, but will Europeans make the effort for a single market if it doesn't give them certain advantages vis-`a-vis non-Europeans? Why give up sovereignty for the privilege of being overrun by foreigners, they may wonder.

This concern is motivating a number of American and Japanese companies to establish a European presence now, before it gets harder later.

Meanwhile, optimistic projections are being made for the next six years of additional jobs that will be created because of the single market (1.8 million); extra economic growth to result from the dropping of barriers (4.5 percent); and cumulative growth of inflation (6.1 percent less than would be the case without a single market).

But estimating what would have been and what might be saved gets one quickly onto mushy statistical ground.

We are inclined to do a little discounting here. Euro-optimism seems to be replacing the Europessimism of a while back, and that is not a bad thing.

One step at a time, though, would seem to be the way for Europe to go. Let it try a unified internal market - if a Eurocurrency becomes necessary, that will be apparent. The EC is not going to be able to force Thatcher or anyone else to give up sovereignty.

But her comments are a reminder of how diverse the small continent is, how many different cultures and peoples make up Europe, and how their concerns will all have to be taken into account for a unified Europe to succeed.