A successful museum is like a successful newspaper: It has personality. The best curators, like the best writers, have convictions and leave fingerprints. Occasionally, there's the added dramatic perk that a single institution will have clashing strong-willed staffers. That's part of what makes this era at the Tacoma Art Museum so interesting.

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Contemporary and Northwest curator Rock Hushka brings a Western, underdog, sociopolitical bent to TAM. Meanwhile, the museum's chief curator, Patricia McDonnell, is an exacting historian specializing in early American modernism. Hushka's big project is a 2009 exhibition on how visual art has shaped the dialogue about AIDS, about which he threatens deliciously, "It's time to push some buttons really hard." McDonnell's magnum opus, open now, is The Great American Thing: Modern Art and National Identity, 1915–1935, a major loan show of 130 artworks and 45 artifacts borrowed from preeminent American art institutions and funded by both the National Endowment for the Humanities and the National Endowment for the Arts. It is legitimacy embodied. To receive funding from the Bush administration, it'd have to be.

Stanford University art historian Wanda Corn sees the show as an excavation, as proof that American modernism began before Clement Greenberg and Jackson Pollock. Fair enough. But this digging party has come and gone. Corn published her thesis in an influential 1999 book—on which the exhibition is based. Scholarship like Corn's inspired greater interest in shows such as Margaret Bourke-White: The Photography of Design, 1927–1936, Marsden Hartley: American Modern, and A Transatlantic Avant-Garde: American Artists in Paris, 1918–1939, all of which have been at TAM in the last three years. That makes The Great American Thing feel like the 101 class after you've already passed the 200 level.

The exhibition fills almost the entire museum, and the art is somewhat micromanaged, divided into six sections marked Introduction, Transatlantic Exchange, Jazz America, Engineered America, Ancestral America, and Spiritual America, with subsections such as Skyscraper Cities, Ocean Crossings, Folk America, and Trees, Leaves, Woods. All in all, the proceedings are short on insight, long on spectacle. This is a blockbuster. It was born when the director of the Figge Art Museum needed something impressive to open her new facility in Davenport, Iowa, last year. She hatched the idea of turning the book into an exhibition, and Corn tapped McDonnell to arrange the loans. McDonnell borrowed excellent examples by all the big names: Alfred Stieglitz, Georgia O'Keeffe, Hartley, Marcel Duchamp, Francis Picabia, Man Ray, Fernand Léger, George Grosz, Charles Demuth, Charles Sheeler, Arthur Dove, Joseph Stella, Romare Bearden, Lois Mailou Jones, Paul Strand, Berenice Abbott, Walker Evans, Edward Weston, Bourke-White. The book is 447 pages with 321 illustrations. The exhibition is as vast as a view across Kansas, and about as penetrating.

Admittedly, the scenery is much better. There are hopping jazz films and a flickering 1921 short movie by Strand and Sheeler. Glamorous artist portraits—a priceless shot of Duchamp and Picabia at a Coney Island funhouse. O'Keeffe's belted black silk kimono. A recording of avant-garde composer George Antheil's clanging Ballet Mécanique, and a great newspaper cartoon it inspired. The earliest digital clock. A bottle of Odol mouthwash. Léger's cubist American flag. Dove's transcendental landscapes. Books praising American industrial architecture by Walter Gropius and Le Corbusier. Ray's gleaming tabletop skyscraper in a vise. Beyond the dapperness of it all, complaints arise, preferences heat up. Where is the Depression? Where is Jacob Lawrence? Stieglitz and O'Keeffe are overrated. Duchamp's ready-mades are not. Demuth, an antecedent for artists from Ruscha to Diebenkorn to Mapplethorpe, deserves an exhibition of his own this size, one including his urinating soldiers.

All of this is academic, in an era of toxic neo-nationalism that no museum would ever get federal funding to explore. Truth is, The Great American Thing is a guilty pleasure, a terrific historical dog-and-pony show that, unfortunately, would have been right on time, culturally and art-historically, about seven years ago. It's also the first blockbuster TAM has organized on its own with a staff curator, which was probably inevitable, given the museum's transfer in 2003 to a designer facility. At least this blockbuster is chic and serious-minded (including a symposium March 11 featuring Corn and Duchamp scholar Francis M. Naumann) instead of bloated and dumbed down. But ultimately, a museum doesn't distinguish itself by flying in objects from New York's museum row. It's a good thing TAM is talking about pushing some buttons really hard, too.