Trade barriers along the 2,000-mile U.S.-Mexico border are getting closer to tumbling down as Congress enters a crucial point in clearing the way for free-trade negotiations.

The proposed free trade agreement between the United States and Mexico, which would eliminate tariffs and other trade restraints, is on a fast track, with negotiations set to begin in March and to be concluded by year's end.Opponents of free trade - including labor unions, environmental groups, textile manufacturers and fruit and vegetable growers - fear massive job losses to cheaper Mexican labor. Yet, far from being adamant in their opposition, most actually favor free trade, but in a "go slow" approach.

On the other hand, supporters, especially Texans, see the prospect of Corpus Christi and San Antonio becoming world trade centers and impoverished Texas border cities becoming major distribution hubs.

Sen. Lloyd Bentsen, D-Texas, readily admits to the importance of courting opponents of the measure. He has suggested that in sensitive areas, trade barriers be reduced gradually, so that assistance could be provided to help workers and companies adjust, retrain and diversify operations.

In a less parochial sense, the destruction of trade barriers would place the Western hemisphere in a better position to compete against an increasingly strong and united European Economic Community.

It would also be a major step in world progress to see the United States and Mexico become effective economic partners.

In fact, cooperation on the economic front might very well improve the prospects for dealing more effectively on such matters as drug trafficking and illegal immigration.

Surely, care and caution can be employed in addressing the concerns of opponents, while at the same time protecting the principle of free trade.