LOOK WEST from the Mall. See the tops of trees on the Virginia side of the Potomac and the Lee Mansion. That inviting vista will be rudely broken if Arlington County continues to approve construction of a 14-story office building near the county courthouse. The National Capital Planning Commission, the group responsible for the look and feel of the area around the federal reservation, argued before the Arlington board that the office building will blight the view from the Mall, damaging the area as a national tourist attraction.

This is just the latest round in a running fight between Arlington and federal planners over the heights of buildings that might intrude on the view from the Mall. The federal government went to court belatedly and lost last year in an effort to block construction of four buildings in Rosslyn.It is also threatening to withhold the benefits of various federal programs if a proposed 24-story building is constructed in Crystal City.

For Arlington County, this fight seems to have become a home-rule issue. Board Chairman Walter L. Frankland Jr. sees the federal government's efforts to limit the size of the most recent building or to prohibit its construction as a brazen attempt to deny his county millions in tax dollars for the sake of maintaining a tree-dotted skyline. But officials of the NCPC see the skyline as a matter of national importance; how the nation's capital looks to visitors from across the land and from abroad.

It is foolish for Arlington to view such large buildings as none of the federal government's business. Requests to lower the heights of some of these buildings are reasonable; some of the county's own residents have questioned not only the height but also the design of them. The county's desire to benefit from the tax dollars generated need not be incompatible with the federal government's desire to have an attractive skyline. New buildings can be handsomely designed and can fit into a skyline that is pleasing to the eye. Arlington does have some responsibility not to blight either itself or the nation's capital as a tourist attraction.