The Smithsonian's American Art Museum and National Portrait Gallery were among the least-popular museums in town, housed in the dank old Patent Office Building at Eighth and F streets NW. The building's centerpiece was an unpleasant, depressing courtyard, dominated by loud, unsightly air ducts.

As part of a five-year, $200 million renovation, the Smithsonian dared to show some imagination: The institution hired one of the planet's most intriguing architects and let him play with the courtyard. It hoped Norman Foster would create a space as magnetic and transcendent as he had in London, where his glass canopy over the courtyard at the British Museum became a joyful gathering place, and in Berlin, where Foster's glass dome for the Reichstag was a popular and artistic hit, symbolizing the reunited Germany's democratic aspirations.

Foster's design for Washington was breathtaking. An undulating ceiling of glass panels would connect our city's 19th-century architectural tributes to Greece and Rome with our 21st-century passion for technological innovation in an open, transparent society. The courtyard -- site of Abe Lincoln's inaugural balls -- would add a contemporary accent while preserving the past. The resulting space would draw tourists, create a snazzy party venue and demonstrate that art is not all obsession with the dead.

But trying to shoehorn the new into Washington's cityscape is never easy. The out-of-towners who run the federal arts commissions are busy rooting out architects' challenges to their fantasy of the capital as 19th-century theme park.

The National Capital Planning Commission (NCPC) sniffed that the canopy, a $38 million project funded entirely by private money, largely thanks to the generous Kogod family, "will further degrade the character of the Patent Office" and cause "adverse effect to the L'Enfant Plan" for Washington. This from the same bunch that permanently marred the Mall with the banal National World War II Memorial.

By a vote of 6 to 5, the commission said last week that the Foster canopy must go. Never mind that artisans are already making the glass panels. Never mind that the canopy was designed not to tower over the museum but rather to hover gently along its roofline, adding a soft note of intrigue to the sameness of the city skyline. Never mind that every local appointee voted for the canopy.

The arts commissions that control the look of the city are an appalling reminder of the District's colonial status. The Commission on Fine Arts controls everything from downtown museums to Georgetown's waterfront to a senior center on upper Georgia Avenue, yet six of its seven members live far away from here. Of the 12 members of the NCPC, only four are locally appointed; the rest are tools of Congress and the president.

Not only has Foster been sent packing, but the Corcoran Gallery of Art's board has spiked Frank Gehry's proposed swirling metallic addition to the museum. Together, these rejections from the City That Says No send a devastating message to designers who might have considered spending their energies on the old convention center site or the new baseball stadium: Forget it -- leave Washington to artists whose vision is to the rear.

"It would be very unfortunate if this and the loss of the Gehry addition sent the message that we're not open to contemporary design," says David Bell, a Washington architect who has studied the canopy issue for the D.C. Preservation League. "A little controversy in design can be a good thing. The places we appreciate now often were controversial when they were designed."

The NCPC opinion prattles on for 16 pages of bureaucratic gobbledygook, which can be summed up in one sentence: How dare you expose this city to the crossfire of artistic ideas?

The same brittle thinking that has turned Washington into an ugly, armed fortress since 9/11 is at play here. These arts commissions had a responsibility to the city and nation in the era of terrorism: Use design to maintain American openness even as we seek to secure potential targets from attack. But the commissions prefer to shut their eyes to the infestation of Jersey barriers and closed-off sidewalks, focusing instead on punishing artists who still believe in the American ideal, who seek to embrace democracy and our history while imagining an even more inspiring future.