THE IMAGE IS still vivid. I was standing on a midtown Washington street corner in the late '60s and a schoolbus painted a dark army green rolled to a stop at a red light. It bore no identifying army markers. The windows were darkened to obstruct the view.

Suddenly a soldier peered out, and I saw the yards of white swathing his dark face and mangled arms. He looked young and afraid. He was being driven with a busload of other wounded Vietnam vets to the Veterans Hospital here. They were brought in late at night so the populace would presumably be spared from facing the brutalities of war.

Listening to President Carter last week, I thought of this, and the shattering images we witnessed on our television screens night after night not too many years back. I thought of the veterans hospital that today are filled with the mangled residue of Vietnam, the veterans who must still get daily doses of morphine. I thought of friends I know who fought daily in that war. It is recent .

The president has called for the reinstitution of registration as a way to locate young men, ages 18 to 26. Drafting is not an inevitable next step and would, of course, require legislaltion.

But if the terrors of war are inevitable, and if the draft must be resumed, let's not repeat the Vietnam experience, in which we made exceptions for so many categories of people that the burden of catching the bullets fell disproportionately on the poorest.

When the buildup occurred in the mid-to-late 1960s here, we in Washington saw the streets swept clear of young men. But not all streets in all neighborhoods were affected. They disproportionately swept up the poor and those who had never been to college. A man I know in town was drafted during this period and rode with these young men to Fort Bragg and later ran into them fighting with rifles in the jungles of Vietnam. Poor whites and poor blacks were in the same jungle.

So if this terrible state of affairs must come, it must not bring with it the same exceptions for the privileged class in America. It must be applied equitably to all young men who are mentally and physically able. That's the only way we can escape the fate of those who bore the brunt of Vietnam.

I was struck, too, by the coincidence that the previous day's front pages had National Urban League President Vernon E. Jordon Jr. bemoaning the shocking news that not only is black unemployment twice that of white unemployment, but it also is getting worse. Obviously international conflict is no contrivance to settle domestic employment, but it will be the height of a terrible irony that those men and women who cannot be found to work will be found to fight.

We all hope we'll see no return to the dying and destruction brought live to our television rooms via satellite. But if it must come in the interest of survival, please Mr. President, let it come with fairness. For only in equity is there truly honor.