SHOULD RESIDENTS of the District of Columbia be able to elect, as residents of all the 50 states can, their own members of the U.S. Senate and House of Representatives? The answer is obvious: yes. D.C. residents pay the same taxes as other Americans. They have been drafted to serve in the same military services. Yet for nearly 200 years they have not had the same right to congressional representation as other Americans. At one time this might have made sense. The District was originally a lightly populated enclave with few permanent residents. But today's District is a diverse, economically expansive community where most citizens are not on the government payroll.

So it shouldn't have been all that surprising that Congress in 1978 passed, by a two-thirds vote in each house, a constitutional amendment giving the people of the District full congressional representation. That was five years ago this week. But most of the states have not yet ratified the amendment. The arguments for the amendment are as strong as the arithmetic, currently, is weak. Only 13 states have ratified, out of the 38 needed: 25 more are needed between now and August 1985.

That sounds daunting, but we don't think it's cause for despair. The pace of ratification has picked up in the last year, and the margins by which the amendment was passed most recently, in Rhode Island (74-6 in the house, 33-7 in the senate), suggest that when the arguments get a full airing, the measure can gather wide support. This is not a partisan measure: many Republicans have supported it, despite the District's Democratic voting preference (although it wouldn't hurt if it got the same enthusiastic support from President Reagan that it has gotten from Sen. Barry Goldwater). The issue shouldn't be which way the District would vote, but whether its 600,000 residents, like the 600,000 residents of North Dakota, should be able to elect the congressman and senators they want.

Unfortunately, the amendment just doesn't seem to be a priority item in many legislatures. Self-Determination for D.C., assisted by Common Cause, has been trying to change that, but these organizations need help. Most state legislatures go back into session next January, and almost every legislature will meet beginning in January 1985--with many new members elected next year. Enthusiastic support from all quarters of the District could help produce a flurry of ratifications next year and make self-determination, finally, a reality for the citizens of the one capital in the free world that cannot choose voting representatives in the national legislature.