FOR ALL OF ITS infinite and tedious complexity, the federal tax code maintains a sense of decency and reason. It has a coherent architecture. You might wonder how that happens since, notoriously, every major tax bill is finally enacted in an atmosphere of extreme confusion, haste, passion and anxiety. For the past 15 years one leading reason for the tax system's integrity was the vigilance of Laurence Neal Woodworth, who died this week. He had joined the Carter administration earlier this year as Assistant Secretary of the Treasury for tax policy, but previously he had been the staff director of the Joint Committee on Taxation.

A tax system is a nation's definition of social equity - its answer to the great question of what's fair. In taxation, the large philosophic issues never lie far behind the niggling legalistic details. The role of the congressional staff experts on taxation is not a comfortable one. The tax committees are generally led by tough and strong-willed men; stakes run high, and no bills are more fiercely lobbied. Under weak leadership, the Joint Committee's staff would have been ground to powder long ago between its two masters in the House and Senate.Under Mr. Woodworth, it built a monumental reputation for impartial and authoritative judgment. When, for example, Congress needed an unimpeachable expert for the ugly job of auditing Mr. Nixon's tax returns, it turned automatically to Mr. Woodworth.

To work effectively, the congressional system requires enormous talent and industry among its staffs. Those qualities are very unevenly distributed through the labyrinths of the congressional offices. But the staff of the Joint Committee on Taxation has become an acknowledged model.Mr. Woodworth always left the political decisions to the politicians, and never tried to undercut them with technical obfuscation. But he worked long into the nights after the committee meetings to ensure that the politicians understood the consequences of their votes. Even the most flamboyant of senators was unlikely to press an idea in the face of Mr. Woodworth's warning that it wouldn't work. His death now is a double misfortune to the Carter administration. He was the key figure in the drafting of the President's tax-revision bills. But he was also the administration's principal ambassador to Congress on this delicate subject, and he had earned a degree of trust and respect there that no other person at the Treasury enjoys.

He was a remarkable example of a certain style of public servant - one who is rarely a noted public figure, but who acquires a profound influence through sheer intellectual force and honesty. His subject was one that touches all of us every day. It is an American custom to complain about the tax system's vices while taking its virtues for granted. They are not accidental, but were written into law by a small number of people - among whom Mr. Woodworth was eminent - who labored with learning and skillin pursuit of the just balance between public and private interests.