he Reagan administration entered negotiations with 52 nations today in a last-ditch effort to negotiate an international agreement that will directly affect the lives of millions of textile workers around the world.

The negotiations, which will involve 2 million textile and clothing workers in the United States, concern the Multifibers Arrangement (MFA), which for the last seven years has set the ground rules for approximately 80 percent of the world's trade in clothing and textiles. The United States has been an active party to the agreement since it was negotiated under the auspices of the General Agreement on Tariffs and Trade in 1973 and has played a leading role in talks on its renewal, which began here in July.

The MFA talks resumed in a mood of cautious optimism as Horst Krenzler of West Germany, head of the delegation of the Common Market (European Economic Community), announced that his group is prepared to play "a full and active role" in the negotiations. The Common Market council of ministers finally decided Tuesday night on a bargaining mandate for their negotiators here. It is generally agreed that the absence of an EEC mandate has been a major obstacle to movement in the talks so far.

Until now, progress in the talks has been stymied by a seemingly unbridgeable gap between the demands of the growing number of Third World exporters (Hong Kong, South Korea and Taiwan, for example) for greater access to the markets of industrialized countries and the demands of the latter, especially the countries of the Common Market, for ever-tighter controls on imports from the developing world, which they blame for the steady decline of their own apparel and cloth industries over the past decade.

The impasse between these two camps has allowed the Reagan administration to occupy a middle position in the MFA talks.

In September, the U. S. delegation to the MFA negotiatons, led by chief U. S. textiles negotiator Peter Murphy, tabled a draft protocol to the MFA, which it claims will ease the access of most Third World exporters to the big markets of the industrialized countries while giving the domestic producers of those countries the protection they need to modernize in order to meet the challenge from developing countries. The main thrust of Murphy's protocol would be to eliminate the so-called "reasonable departures clause" from the MFA. Third World exporters charge that the clause has allowed the EEC to carry out wholesale restrictions on their exports.

The United States wants to replace it with tighter rules on what countries can get away with when they claim to be deluged by imports. This proposal generally has been pleasing to Third World exporters and, so far, anathema to the EEC.