So many brick bouquets have been thrown in the general direction of the Hart Senate Office Building, which officially opened this week after nearly a decade of construction and constant controversy, that one would like to be able to toss it a garland of real flowers. But it's hard. Arm cocked, flowers-at-the-ready . . . no throw.

The Hart building may not be the total esthetic and symbolic disaster it often is cooked up to be, but it is bad enough on both counts. Designed by John Carl Warnecke & Associates under the aegis of George M. White, architect of the Capitol, the new structure was meant to be a background building, subservient to the Capitol itself, and it strives far too mightily to accomplish this goal. It is a building literally clothed in irony, immodest in its modesty, gargantuan in its search for the human scale, and marble (and marble, marble, marble) in its modernism.

So where's the good word, the half-Harted cheer? Well, take a stroll in the glorious precincts of the Capitol, or simply recall to the mind's eye what happened the last two times the Congress decided to build. To say that the Hart building represents an improvement over the last-gasp architectural decrepitude of the Madison Library and the Rayburn House Office Building may not be saying much. But, keeping the Capitol Hill master plan firmly in mind, it is a point worth making.

That plan, published last fall, contained many good points, but it also contemplated a truly enormous increase in congressional office buildings on both the Senate and House sides of the Hill. If even a part of this vision materializes, Congress will continue to cover the terrain with outsized mistakes, or it will, at some point, have to recapture the art of building buildings that serve day-to-day needs and, if not elevate, at least calm the soul.

If the Hart building simply represents the end of witless, desicated attempts to reinvent the wheel of classical architecture, if it represents the beginning of an effort to bring congressional buildings into accord with the best architecture of our own time, then it will have done some good. But that is perhaps to expect too much, for the new building is almost as frightfully Brobdingnagian as its immediate predecessors on the Hill, and it is hopelessly out of tune with the more sensitive, innovative thinking among contemporary architects.

It is out of tune with its immediate neighbors, as well. To walk along Constitution Avenue from the Russell building to the Dirksen to the Hart is to witness a definite, progressive decline in architectural finesse. The Russell building (1906, Carrere and Hastings, architects) is a typical and quite a good example of Beaux Arts classicism: long, low, richly textured from base to cornice, beautifully and a bit theatrically modulated at the corners, with colonnades and pediments in all the right places. Because of its scale and its shared vocabulary of form and ornament, it treats the Capitol with quiet respect -- a background building that holds its own. The Dirksen building (1958, Eggers and Higgins, architects) plays weak sister to the Russell, trying with only partial success to make up in the refinement of its stripped classicism (note the elegant bronze window spandrels with their delicate sculptures in relief) what it lacks in vigor.

The Hart building is bigger than its neighbors, but it sorely lacks refinement and its vigor is of the bullying sort. It is in all major respects save one -- the sheathing of white Vermont marble -- a typical modernist office structure, from its beehive sunscreen facades (necessary to screen the sun only on the south side, of course) to its cavernous interior atrium.

Sheathing the building in marble is superficially defensible from a contextural point of view--the building abuts the white marble facade of the Dirksen structure -- but in fact all that whiteness serves mainly to throw the "background" building prominently into the foreground. (Acres and acres of the precious stuff, even on Capitol Hill -- perhaps especially on Capitol Hill -- do not make a masterpiece.) The Hart building is only technically an addition to the Dirksen; in all respects it looks like, feels like and in fact wants to be a structure standing free and clear of its surroundings.

The building appears to have been designed from the inside out, not necessarily a bad thing but in this case the result of misdirected good intentions. The two-story sunscreens that establish the building's massive presence, for instance, result from the decision to put the two-story senatorial chambers on the outside ring of the building. From inside the offices, this looks fine. You can hardly begrudge a U.S. senator a high-ceilinged room to work in, and besides, what constituent would want to visit his legislator in some tacky little cube? Still, on the outside it creates a sadly monotonous appearance that is, needless to say, thoroughly discontinuous with the lines of the adjoining Dirksen building.

The praiseworthy desire to bring light and air into the working lives of Senate staff people, who often must get the feeling they've been spending their best years in a labyrinth of airless cubes and endless hallways, produced the vast skylit cube of the interior atrium and the two towering wings, or "gallerias," running through the building on a north-south axis.

This does indeed make a welcome change in the usual dreary walk to and from offices, and it should be said that there are a few very elegant architectural touches involved. When visiting the building, look especially for the two "ceremonial" stairwells -- half-circles running the entire height of the building with skylights at the top. They are nicely done.

But for all that light and air the atrium is a particularly joyless space, rather like a prison yard with marble walls and floors, or a 1970s hotel without the plants and dipsy sculpture. In addition to this insensitivity, the very size of the atrium forced the building to become much larger than it really should have been in this special spot. To be fair I should say that it is awesomely empty at present, both of people and of trees -- much needed improvements. And then there is the missing sculpture. Designed for the space by Alexander Calder, a huge steel piece combining stabile and mobile was cut from the budget as if it were some inconsequential frill.

Still, one wonders if this behemoth space, a cliche' of the "people place" decade of the 1970s, was not the wrong answer to the right question, something, come to think of it, that might fairly be said about the Hart building in its entirety.