BY THE SLIMMEST of margins, Maryland's House of Delegates once again -- and this was it for the year at least and probably much longer -- has refused to ratify the constitutional amendment that would allow congressional representation for the District of Columbia. While it's one thing for people in faraway states to resist the proposal, this action by the District's neighbors has made it distressingly clear that the amendment is in bad shape -- that only time, a national change of heart and some miracle can combine to save it.

So now maybe all of those opponents in Maryland who argued that retrocession of the District to Maryland would be preferable to the amendment will stick to their guns and kick off the campaign to take this city into their fold. After all, there are three-quarters of a million residents here; that's at least enough to establish a county that would have its own delegation in the state senate and house of delegates. Then if the District members of the Maryland General General Assembly team up with their friendly colleagues from Montgomery and Prince George's counties and Baltimore City, they should be able to outvote the delegations that joined to defeat ratification last week.

This is nonsense, of course, just as it was when opponents threw it out as an alternative to the amendment. But now that Maryland has joined the list of states that have rejected the amendment, oponents in other states will find retrocession all the more useful as an excuse for dontinuing to deny the citiaens of the District the representation in Congress that all other tax-paying Americans enjoy. Fortunately, the states that are saying no this year -- including Maryland -- do have years to reconsider. We can only hope that their mood as well as their understanding of this issue will somehow improve enough to turn things around in the name of simple justice.