A dramatic plaza with a semicircle of presidential statues and a moatlike ramp would protect the east side of the White House against would-be terrorists under a plan proposed by architect Arthur Cotton Moore.

Moore offered the design in April as part of a long-range master plan for renovation of the Treasury Department -- a plan commissioned by former secretary of the Treasury Donald Regan. But no action has been taken on the proposal, and Treasury officials under new Secretary James Baker apparently have no plans to take any in the near future.

Moore had expected to make a formal presentation of the plan -- for which he was paid $60,000 -- to Treasury officials, but said yesterday he was never asked to do so.

Paul Cooksey, deputy assistant secretary for administration, said yesterday implementation of the plaza plan would be "imprudent" in these budget cutting days. "Right now, we're just working to preserve the architectural qualities we have," Cooksey said, "and maintain the building so it won't fall down."

The 50,000-square-foot Presidential Plaza would form a ceremonial end to Pennsylvania Avenue on its highly visible route westward from the Capitol. Architects have long worried that L'Enfant's grand avenue, which he designed to end with the White House, runs smack into the Treasury Building at 15th Street instead. Andrew Jackson ordered the Treasury put where it is, according to legend, so that Congress couldn't keep an eye on the White House.

The plaza would encompass the south grassy lawns and rose gardens of the Treasury, Alexander Hamilton Place (a small street now closed off on the west by barriers and used for parking) and the south section of East Executive Avenue.

Moore said his idea aimed primarily "to propose an esthetic substitute for the 'New Jersey bunkers' " -- concrete barriers installed in a ring around the White House, in response to recent concern about terrorists. Security officials especially worry about trucks carrying bombs being able to get a running start and thus enough momentum to crash though White House grounds.

His plan, Moore said, also aims at getting White House tourists off the street and out of the rain. A small, partly underground 20,000-squarefoot museum would serve as a holding area and interpretive center for White House tourist tours. Moore suggested that metal detectors and other screening devices could be installed in the area. Permit parking for 750 cars would go under the plaza, to be entered by the East Executive Avenue ramp.

Because of the lay of the land, the west side of the museum would be completely underground. Its east wall would be 10 feet high, pierced by a wide gate, set between two pylons, serving as guardhouses, to protect the east entrance of Alexander Hamilton Place.

The semicircle of granite statues of presidents would be the second line of defense. Moore says several half circles would fit, enough to accommodate presidents "into several millennia." Beyond the statues, the ramp leading to the underground parking would serve, Moore said, "as a moat."

Moore's gate design is enlarged from the 1836 design by Robert Mills, the original architect of the Treasury. The statuary circle is reminiscent of another proposal by Mills in his 1848 award-winning competition for the Washington Monument -- a circular Greek peristyle temple around the base of the obelisk. The temple fell victim to cost constraints and was never built.

Moore, a sixth-generation Washingtonian, is architect of such Washington landmarks as the remodeled Old Post Office Building just down Pennsylvania Avenue and the controversial Washington Harbour project on the Georgetown waterfront. He said he would still like the plaza plan to be considered seriously, but thought it a bad omen that 30 of the plan's 191 pages were reported to have been lost in the Treasury's copier room.