Guess which is bigger: the art or the argument?

NORTH ADAMS, Mass. -- From the day MASS MoCA opened in 1999, its defining space has been Building 5, the gallery almost invariably described as "football-field-sized," meaning it was big enough to accommodate Robert Rauschenberg's "The 1/4 Mile or 2 Furlong Piece," 206 panels of painting and collage, or Robert Wilson's "14 Stations," a Shaker Village reflecting on Jesus' final march, or Tim Hawkinson's "Überorgan," balloon-like creations that seemed a cross between giant human bladders and bagpipes that bellowed tones as visitors passed.

"It's how people remember when they were at MASS MoCA," says Joe Thompson, director of the museum in a factory that once made Civil War uniforms. "They'll say, 'I was there the year exploding cars were floating through the gallery.' "

What many will remember from this summer, however, is how yellow tarps obscured what figured to be the most ambitious installation ever in Building 5.

True, they can get glimpses, above the tarps, of the bigger components of what was to be Swiss artist Christoph Buchel's "Training Ground for Democracy" -- an entire two-story Cape Cod house, stacked cargo containers and a towering cinder-block wall alongside a re-creation of the "spider hole" in which Saddam Hussein hid in Iraq. And if they peek under the tarps, before a guard shoos them away, they may see hazardous waste containers or a swing-around carnival ride in which bombs replace the usual child-friendly miniature airplanes.

It was going to be a commentary on America's efforts to remake the world through war and other means. Instead "Training Ground for Democracy" has become an expensive lesson in what can go wrong when a risk-taking museum partners with a risk-taking artist.

In May, the museum announced it was canceling the exhibit because it was behind schedule, over budget and facing its creator's demands for more costly components -- notably a jet fuselage. The museum said it was going to federal court to win permission to show the unfinished piece as a "back-lot workshop . . . providing important insight into the intricacies of creating art in our time and day."

That's when Buchel countersued to keep the museum from doing any such thing and asked for damages, alleging that MASS MoCA had failed to provide materials it promised and was violating the federal Visual Artists Rights Act by showing his incomplete creation.