FOR MORE THAN a dozen years, members of the all-male Cosmos Club have been considering whether to admit women to their exalted company. But the handsome -- nay, revolutionary -- decision in 1972 to let female guests use the front door (they used to have to go in a separate entrance) seems to have represented the outer limits of the membership's tolerance. All efforts since then to really open the door to women have failed.

The Cosmos Club is, of course, a private organization, so members have a right to make their own rules. But there is something highly comic about these rules as the handiwork of a contemporary group with such immodest aspirations. For the Cosmos Club styles itself a "national institution of scientific, scholarly, cultural and educational interests." It is an institution that must, however, by its own directive, continue to exclude a number of extremely distinguished prospective members -- judges, teachers, scientists, government officials and the odd Nobel Prize winner -- whom it considers permanently and irreparably blighted by having been born female. It is enough, surely -- this line of reasoning seems to go -- that these unfortunates are nowadays admitted through the front door. What on earth do they and their many champions within the club (those troublemakers) want?

This year the club's board of management has launched an offensive with the apparent purpose of ending even discussion and debate on the question of admitting women. In May, officers announced a new policy of requiring prospective members to sign a pledge agreeing not to work to change the bylaws excluding women. That idea has since been abandoned, but new members will be interviewed and asked to sign a statement that they are aware of and not "embarrassed in any way" by the policy -- a watered-down loyalty oath, right up there on Massachusetts Avenue!

Even more ludicrous is the board's attempt to suspend or expel Samuel P. Hayes, a distinguished 75-year-old retired economist who is chairman of the 450-member committee pressing for change. The managers have served papers on Mr. Hayes charging that his efforts over the past five years to inform and persuade fellow members -- sending three letters to the membership and supporting certain candidates for the board -- are "boorish and ungentlemanly." Mr. Hayes, it seems, has become a "pest" because he wants to discuss an issue that a majority of the members prefers to ignore. His attempt to change the bylaws through ordinary democratic procedures is considered "obtrusive," "confrontational" and "strident."

The Cosmos Club officials behind all this are doing Mr. Hayes no real harm. But they are making perfect fools of themselves and their institution.