As an early sponsor of the Metro system, I read with interest Secretary of Transportation Samuel Skinner's Close to Home article on Metro's future {May 27}. Mr. Skinner, who called Metro "outstanding" and "a credit to the community," nonetheless wants to curtail federal funding for the completion of the 103-mile system. That contradiction needs consideration.

First, Mr. Skinner argued that Metro is "a local transit system serving overwhelming local needs" and concluded that those who benefit most should pay a larger share of construction costs as a matter of fairness. He's right about that -- those who benefit most should pay the most, and one of the largest beneficiaries of Metrorail is the federal government.

It was Congress and the executive branch of our government that decided on a 103-mile system and planned it around federal needs. More than half of all Metro stations directly serve federal agencies, including the Pentagon, the Federal Triangle and, of particular interest to Mr. Skinner, the Department of Transportation.

All major federal agencies are within a few blocks of subway stops. Every day Metro carries more than 400,000 workers to and from their jobs with the city's largest employer -- the federal government. Obviously, the federal government benefits hugely from the Metro system.

Second, many federal employees are lower-income workers who live in the areas yet to be served. These workers and their neighbors should not be denied access to the metropolitan transit system. They, more than most, need access to Metro in order to take advantage of employment and educational opportunities throughout the area.

Third, Mr. Skinner maintained that "funds to build WMATA should not come from a new piece of special legislation." But who's talking about new legislation? When Congress first developed the Metro plan, it wisely provided for a special funding relationship between the federal and the local governments. Maryland, Virginia and the District have met their financial commitments. The federal government is trying to avoid doing the same with this argument about subways being a local affair.

By way of example, the secretary pointed to cities such as Los Angeles and Chicago that finance their transit systems without a special arrangement with the federal government. However, the largest employers in those cities pay substantial taxes to the local government, taxes that go in part to support a transit system. Here, of course, the federal government is exempt from local taxes. Does that mean it should be exempt from its obligation to support the completion of the transit system?

In the past 25 years, much has changed in the D.C. area. When I was a freshman member of Congress, driving through Maryland to my home in Frederick, I passed through miles of fertile farmland. Today most of those farms have been replaced with subdivisions. The narrow highways I traveled are multi-lane and carry many more cars. Without Metro, as Mr. Skinner must surely realize, our traffic problems would already be of crisis proportion.

Finally, there is a perhaps less tangible, but no less important reason why Metro must be built. In London, Paris and Moscow, efficient subway systems serve not only local and governmental needs but also international visitors. They are emblematic of their countries. For many foreign visitors, Washington is the United States, and Metro is America's subway. For reasons both practical and symbolic, the corners of our nation's capital should be joined together by its completion.

CHARLES McC. MATHIAS Chevy Chase The writer, a former Republican senator from Maryland, was chairman of the Senate Governmental Affairs subcommittee on the District.