Today the Vietnam Veterans Memorial has transcended its role as a national symbol of reconciliation and stands as a living history lesson. The memorial is unique in its ability to inspire exploration and reflection about this critical time in our nation's past, with a wiser eye toward the future.

Congress is about to alter the site of the memorial again. Rep. Elton Gallegly (R-Calif.) has introduced legislation that will add a plaque at the wall honoring veterans who died from Agent Orange-related cancer, post-traumatic-stress-disorder-induced suicide and other ailments related to service in the Vietnam War.

To date, more than 100 members of Congress have co-sponsored this legislation. And also behind the effort is retired Adm. Elmo Zumwalt, whose son died from cancer, possibly caused by Agent Orange. Zumwalt accepts responsibility for the part he played in carrying out the government's policy to use the Agent Orange defoliant in the war.

But this is not the first time Congress has tried to modify the memorial. As a concession to veterans who wanted a more traditional memorial, the "Three Servicemen" statue was added to the site in 1984. And almost 10 years later, a group of four statues was added on the site to honor the women who served in Vietnam.

And over the years, myriad other changes and additions to the memorial have been proposed.

Former congressman Bob Dornan made spirited efforts to place a flagpole at the apex of the memorial. Other proposals are in the works:

A military scout dog memorial. A Native American soldier memorial. A Hispanic soldier memorial. A monument honoring the 2 million Vietnamese who died. A monument for merchant sailors. CIA agents. Even inscribing the names of the Kent State students killed in 1970 onto the wall.

And the lobbying continues. The wall could become a backdrop for a sculpture garden of plaques and statues. Each of the proposed additions has constituencies just as sincere and well-meaning as those requesting a plaque.

The Vietnam Veterans Memorial Fund built the wall in 1982. We continue to be involved with the wall, paying for needs such as engraving names, uniforms for volunteers or anything else needed to assist the National Park Service.

We have no objection to a plaque, if normal design-review procedures are followed and if the legislation permanently halts all future efforts to legislate additions to the memorial. Could Congress restrain itself?

Great works of art such as the Iwo Jima Memorial, the Jefferson Memorial and the Vietnam Veterans Memorial do not need to be "improved" by legislative bodies.

The writer is president of the Vietnam Veterans Memorial Fund.