The United States’s contribution to the 51st Venice Biennale consisted of 10 paintings by Ed Ruscha, an artist who is inevitably linked – through subject matter and the fact that he lives there – with Los Angeles, and who has been very much in vogue in recent years. Indeed, because he is so “in,” I was disappointed when I first heard he’d been chosen. Couldn’t the Americans, like the Austrians and the Australians,have picked a younger and less famous representative, someone who would indicate where we are going artistically, rather than where we’ve been? Now, however, I think I was perhaps wrong, and that “where we’ve been” is the crux of the matter.

Regardless of whether you call him a Pop artist or something else, Mr. Ruscha has always been a nostalgist of a distinctly American sort. And nostalgia has always been a fundamental part of the American character, be it 1835 or 2005. We are a nation born of, and obsessed by, progress – of change and betterment. Change is inevitably accompanied by a nostalgia for what was: the decade of our childhood; an old Europe some of our ancestors left behind; an imagined golden era; a pre-lapsarian wilderness; an old building that’s no longer there; or even just the company that used to occupy that building.

This progress-born, American-type nostalgia animates Mr. Ruscha’s Biennale contribution, “Course of Empire,” which is on view beginning today in a beautifully simple installation at the Whitney Museum. Two walls pair five black-and-white “urban landscape” paintings from the artist’s 1992 “Blue Collar” series – the springboard and inspiration for the cycle he eventually made – with five color paintings created in response over the last two years.All are painted on large, horizontally formatted canvases.

The title for Mr. Ruscha’s cycle comes from the American painter Thomas Cole’s series of five paintings, completed in 1836. In Cole’s “The Course of Empire,” he illustrated the birth, rise, and desolation of an imagined – and notably Venetian-looking – empire. Lacking the deterministic “The,” Mr. Ruscha’s “Course” set out to marry the monochrome canvases with, in his words, “an accelerated, aged version of the same urban landscapes, possibly to the point of deterioration.” Still, his cycle seems more optimistic, or at least more open to an optimistic future, than Cole’s.

Consider the first pairing, which to me seems the most damning. In “Blue Collar Tech-Chem” (1992), a severe, unornamented gray building with a single, tiny door and the words “TECHCHEM” inscribed on one wall, squats beneath a dark, lowering sky. Its companion,”The Old Tech-Chem Building” (2003), shows the same edifice with significant renovations.

Four large bays, or possibly windows, have been opened on the wall where the tiny door once stood and, in a nostalgic touch, the ghost of its old signage is still legible adjacent to new red letters that spell out “FAT BOY.” A lurid red sky marred by dark clouds perhaps reinforces the nuclear allusion: The two atomic bombs the U.S. dropped at the end of World War II were called Little Boy and Fat Man. Then again, it might conjure thoughts of Fat Burger, the L.A. chain, as well as the obesity that has been visited upon a wealthy America.

However one takes the changes, there can be no argument that the newer paintings are in color – to me this suggests a strain of optimism. The lowslung Tool & Die Building in the next pairing, also under dark clouds, has undergone a more interesting renovation in “The Old Tool & Die Building” (2004), in which its signage (and pre sumably the company) has been replaced by Asian characters (largely meaningless, according to the catalog), and its sky has turned to a smoggy pinkish green. Low on a side wall, Mr. Ruscha has expertly painted a length of graffiti, including, it should be noted, a swastika.

So has bleak industrialism been replaced by colorful immigration, unfortunately undercut by racial strife? Perhaps. Of greater interest to me was the degree to which this newer canvas resembles those painted by the outstanding young British artist Nigel Cooke, who tends to include walls with graffiti and restrict his imagery to the bottom edges of his canvases. Mr. Ruscha has been an example to and influence on young artists for more than a decade now; that he might be looking at them as they look at him struck me as especially intriguing, as well as providing another, deeper, layer of optimism.

Similarly intriguing is “Blue Collar Telephone” (1992), in which the top portion of a telephone booth squats along the bottom edge of the canvas, under a dark sky, in much the same way and at the same scale as the buildings in the series. Its companion, “Site of a Former Telephone Booth” (2005), brackets the empty space where the booth stood – just blue sky now – with a concrete signpost and a peeling birch trunk. The phone booth, which once loomed as large in our minds as buildings, has been deleted from the urban scene. Yet the succeeding landscape is anything but bleak. Is this decline or progress or what?

One might say that, like Cole’s description of his series – but unlike his execution – it is simply “illustrative of the mutation of earthly things,” neither entirely approving nor entirely disapproving. Need we see the “Expansion of the Old Tires Building” (2005), with its empty, tacked-on facade, as a bad thing? No. But we certainly hanker after the simple (and Mr. Ruscha tends to depict his buildings as stripped down by memory), dependable Tires building, just as we are eager for whatever the building will be transformed into.

Like the buildings they portray, these stark images roil the emotions as well as the intellect. And when it is gone, this exhibition will doubtless sit fondly in my memory.

Until January 29 (945 Madison Avenue at 75th Street, 800-WHITNEY).