The Corcoran Gallery of Art has chosen famed architect Frank Gehry to design its proposed internal make-over and expansion. It is at once an audacious and perilous choice.

In real estate parlance, it has potentially great upside benefits but notable downside risks, both aesthetic and economic.

On the upside, the Corcoran stands to gain a landmark work of architectural art, a radical juxtaposition of old and new celebrating dramatic contrast rather than comfortable replication. The District stands to gain a bold, building-scale sculpture adjacent to its monumental core, demonstrating that stylistic diversity can complement the pervasive neoclassical architecture of the nation's capital.

On the downside, as Gehry's design evolves in the coming year it could cost significantly more to build than anticipated. Budget constraints could then force undesirable compromises. Aesthetically, the Gehry addition could prove visually awkward in its marriage to the original Beaux Arts building facing 17th Street, designed in the mid-1890s by Ernest Flagg, and the 1928 addition facing E Street, designed by Charles Platt.

Perhaps the greatest aesthetic risk, however, is that Gehry's Corcoran addition could become just a knockoff of his own work, a formulaic repetition borrowed from structures he has designed elsewhere.

Notwithstanding these prospects, why is so much attention being paid to the selection of an architect for a project whose design is barely underway?

The Corcoran Gallery of Art, the city's first museum, and the Corcoran School of Art are vital cultural institutions occupying one of the city's most originally composed 19th-century neoclassical buildings. Moreover, the Corcoran is only a stone's throw from the Ellipse and White House, the Old Executive Office Building and the Octagon House. Down 17th Street are the Daughters of the American Revolution and the Organization of American States. Consequently, the architectural heritage of the Corcoran and its esteemed neighbors is of great interest to many Washingtonians.

Then there is interest in the work of Frank Gehry, 70, the nation's most celebrated signature architect, whose provocative, idiosyncratic buildings have brought him worldwide recognition. Gehry's sculpturally expressive style of design is well known, especially since the acclaimed Guggenheim Museum in Bilbao, Spain, was completed in 1997.

Can Washington handle a multistory collage of curvilinear, twisted surfaces, clad in titanium or stainless steel or stucco or whatever, undulating and thrusting vertically, horizontally and diagonally, as if in motion?

One of three schemes presented to the Corcoran's Architectural Selection Committee--the other competitors were Santiago Calatrava and Daniel Libeskind--Gehry's concept is well considered.

Sketched in drawings and models, the design adroitly responds to difficult requirements: the need for underground parking; complex horizontal and vertical circulation patterns weaving through nine floor levels; extensive, diverse exhibition spaces with museum support services; and expanded educational facilities.

At the same time, the Corcoran's historic buildings had to be respected.

Because a large setback exposes much of the Corcoran site's northwestern corner, the addition can be an "object" building, half of it virtually free-standing.

David Levy, president and director of the Corcoran, said Gehry won the day in part because he focused most of his presentation on functions within the building, rather than rambling on about aesthetic philosophy.

In fact, behind and under the undulating planes is a relatively logical arrangement of rooms, most conventionally shaped.

This clearly was a wise and winning strategy. Gehry understands that clients usually want to know how well a proposed design solves or eliminates their problems, responds to their needs and respects their budget. Most clients prefer to formulate their own aesthetic judgments based on what is presented graphically, not by listening to extensive lectures on beauty and meaning, no matter how poetically delivered.

But the Corcoran had an aesthetic agenda as well as a functional one. The Corcoran intends its new addition to be no less an artful composition than a sculpture or painting displayed in one of its galleries.

Levy also noted that while the Corcoran has a responsibility to preserve its neoclassical building, it also has an obligation to nurture and present to the public new and controversial aesthetic ideas, to explore and foster innovation in both art and architecture.

"It would be an insult to Flagg's building," considered by Levy to be the "greatest piece of art in the collection," to replicate or mimic it. Creating a new piece of cutting-edge urban art, crafted by today's most inventive designer, is the Corcoran's goal.

To Levy and the Corcoran trustees, it's time to acquire a Gehry and put it permanently on display. It is also an opportunity to become an even more magnetic Washington destination for those interested in the content of its galleries and its architecture. Like the Guggenheim museums in New York and Bilbao, the Corcoran wants to make an architectural statement attracting attention and drawing visitors.

If the city embraces the Corcoran's new building, conservative attitudes about design could soften and life could become somewhat easier for architects and clients striving to depart from the norm. One Gehry might be enough for the District, but there is room for other design ideas that don't bow to neoclassicism.

Finally, we should remember how truly idiosyncratic and personally expressive Gehry's work is. His buildings are not suitable for duplication or cloning, nor are they appropriate models for 99 percent of the buildings that society needs. Gehry's expressive design language may be perfect for the Corcoran, but the architectural scene could get noisy if too many Gehry derivatives appeared.

Roger K. Lewis is a practicing architect and a professor of architecture at the University of Maryland.