WE HAVE YET TO FIND anyone who advocates the desecration of the Potomac shoreline - but when you start talking about what should or shouldn't be allowed to happen along the river's banks, the views vary. For one thing, your view may depend on which side you're on, and what you see from that side of the water. That is why many Arlingtonians may not feel the same way Interior Secretary Cecil D. Andrus does about high-rise construction planned for Rosslyn. Mr. Andrus has asked his department's lawyers to advise him if the federal government can sue developers to stop construction of buildings that would rise to 22, 24, and 29 stories - considerably above limits now imposed on buildings in either the District or Arlington. While this federal concern may be legally proper, it comes too late, long after local plans were first being considered.

The Arlington high-rises have been approved over a period of several years. National Park Service offiicials argue, however, that there was little publicity and inadequate notice of the impact that the buildings would have on the view from Washington. Considering the view now - those ever-so-uniform blocks with the windows all at the same level - maybe some ups and downs and different design would help things. In any event, Arlington planners note that the required legal notice was given federal agencies. In fact, last month, Arlington County Board members turned aside requests from four federal agencies that they reconsider plans for the area on a river bluff overlooking the Kennedy Center and much of the Mall.

Certainly the federal government has an interest in what can be seen from the nation's capital. But it's not fair for federal agencies to fail to act when they have the opportunity to do so and then seek to overturn local government actions. That is one of the reasons that this case differs from another shoreline controversy that has caught the attention of the Interior Secretary. Mr. Andrus also has instructed Interior lawyers to take any legal action possible under federal laws against developer Charles M. Fairchild, who cut down hundreds of trees on land along the George Washington Memorial Parkway south of National Airport. In this instance, the developer is charged with violating an Alexandria tree ordinance; and the federal government's interest is direct - since the park service decides whether or not to approve a bridge-interchange that would link the development to the federally-maintained parkway. We have opposed the project on a number of grounds, including the awful traffic problems it would pose. So whatever the federal government can do to join Alexandria officials in stopping this project would be most welcome.