FOR REASONS that have roots in the history of this country's birth, Americans generally are not aware of the important role blacks played in the Revolutionary War. But one most aware person is Maurice A. Barboza, whose great-great-grandfather was one of some 5,000 blacks who served in the revolutionary military. For the past seven or so years, Mr. Barboza has been doing all he can to make sure this country doesn't forget the contributions of blacks to major battles of the Revolution. His quest -- which has won bipartisan support from Congress, the White House and a range of civic and veterans' groups -- is for a memorial to these troops, to be built on a knoll in Constitution Gardens. Funds for the memorial -- some $4 million in private donations -- are being raised while the necessary approvals for the site are being sought.

Last year, Congress approved and President Reagan signed a bill authorizing the memorial on federal land here. A Republican representative from Connecticut, Nancy L. Johnson, and a Democratic senator from Tennessee, Albert Gore Jr., sponsored the measure. Approvals also are necessary from the National Capital Memorial Commission, the secretary of the interior; Congress again, for the specific site; the Fine Arts Commission and the National Capital Planning Commission.

These complex procedures stem from a sensible decision by Congress not to approve memorials on the Mall without serious justifications for them. There aren't that many sites left. But this project does stand out. Of 110 outdoor national monuments in Washington, there is only one in memory of a black person: educator Mary McLeod Bethune. As Mr. Barboza has noted, "This is not just a memorial for black people. It's a memorial to a concept that transcends color: freedom."

That's a worthy campaign. As Rep. Johnson told Congress, "This memorial will freeze in time a message that I believe the nation's black forefathers would have wanted to leave to their black and white countrymen of future generations: Freedom and independence are worth fighting and dying for. We served so that you would someday be able to live together in harmony."