At the Canadian border in Blaine, Washington, the grass is perfectly green and a white arch representing peace stretches overhead. This is the opposite of the chaos and inequity at Tijuana, and yet this place has its own cold tenseness. Last week, piles of cocaine were seized and people jailed; last year, a man was shot at trying to drive a stolen minivan through. Here, a white lie might be a crime. Speaking to the guards is vaguely nerve-­racking. It feels like anything you say will be the wrong thing. The air is thick—and this thick air permeates the new permanent sculpture that faces you when you cross the border into the United States from Canada. The sculpture is a web of welded-together blackened metal rods, each one small enough to hold in your hand, but all together forming what looks like the negative form of a commercial billboard, 50 feet wide by 30 feet tall. In the center where the sign would go, there is just empty air. Or, as the case is here, not at all empty air.

The artists of this piece are Annie Han and Daniel Mihalyo of Seattle. (In 2006, they won the Stranger Genius Award in visual art; they work under the name Lead Pencil Studio and are also active architects.) They were hired by the General Services Administration (GSA), which is the federal government's property management arm. Law dictates that a portion of public construction funds be used for public art; the Peace Arch Entry at Blaine needed to be expanded, so part of the money was directed to commissioning an artwork. It wasn't an easy commission.

"Here we are doing a permanent piece that's gonna be there forever, after my death, and it's the first thing you see when you enter the United States," Han says. "And then, to put an artwork in a place where people cannot stop and look, which is totally the opposite of the reason you make art usually."

There are places here where you can stop and look—if you're in trouble. The only place everybody passes is a grassy knoll directly in front of the inspection canopy. You drive toward it after the guards release you, then veer left around it and onto I-5.

A man recently stopped his car in front of the art on the grassy knoll, got out, and started snapping pictures. "Red! Red! Red!" the guards yelled. They tackled him and took him in for questioning. The art is not their favorite thing. The precise rules about taking pictures of it are unclear, and a lack of clarity makes everybody nervous at international borders. Having been discouraged from taking pictures but not quite forbidden, I slowed the car a little as I drove past, shoved the camera toward the window, and snapped. I didn't come close to hitting the other merging cars, but my passenger kept her eyes stubbornly forward in what I took to be a slightly scolding way.

"I'm really worried it's going to cause so much trouble that they're going to move it—that it's going to become a Tilted Arc thing," Mihalyo said, referring to the abstract sculpture Richard Serra installed in a plaza in New York in 1981, which became so unpopular that it was removed.

"My opinion stays with me," said one guard, remaining threateningly silent behind his Oakleys.

Another just said, "Oh, it's art," as he waved my car through.

What is it? That's the question people ask. If it were easier to answer, the art wouldn't be as good as it is.

"It's a piece that negates itself," Mihalyo said. "The guards want to be able to say it's a monument or it's a sculpture, but instead they have to say it's Non-Sign."

"The title is Non-Sign II," an older guard told me, dragging out the words as if he were malfunctioning. He was no longer speaking the clipped, concrete language of border interactions: Purpose of visit? The words Non-Sign II (the first Non-Sign was an architectural model exhibited at the Henry Art Gallery in 2006), in the mouth of the guard, expressed the whole, insoluble conflict in one fell swoop.

"We had a fear that we would be edited," Han admitted.

They never were. But is it any wonder, then, that they made a non-sign? A thing that speaks by not saying anything? That's in the process of either materializing or de­materializing, like smoke, but that's never fully there and never not there? It's the opposite of your identity at the moment you cross, all the parts and details and stories that get funneled down to either yes, you can go, or no. In the eyes of the law, the only identities are criminal and noncriminal. The billboard is a reminder of the displacement of everything else about you. It's a friend. It's the last moment of emptiness you'll have before you roll up your window, come back into yourself, and drive on in privacy.

The artists carefully designed the height of the knoll and the specific location of the work on the knoll. As you cross the border from the truck lane, the empty center of the billboard is momentarily filled with a real sign off in the distance that says "USA Gasoline." It advertises a gas station that's on the east side of the freeway—and implies a somewhat unintended direct political agenda for the work. "We were really aware that anything that you do in this environment is going to be inherently political, so it was important for us that the work itself not try to add another political statement directly on top of that, at least not up front," Mihalyo said.

In most of the lanes, the artwork frames a far less fixed view—of open sky with maybe a few trees in the rural area, maybe a sliver of the pretty Semiahmoo Bay, or a slice of a train riding the tracks by the bay. Whatever view you get, it moves right through the frame anyway, because you have to keep the car moving. What you see is transient, fugitive. Not words the law likes.

Yet there are other, more reassuring words that just as easily apply to Non-Sign—its opaqueness withstanding even in description: "the splendor of the natural environment," for instance. That's from the plaque that will go up soon nearby, reading "Borrowing the highly effective quality of a billboard's ability to draw attention away from the natural surroundings, this ephemeral duplicate redirects viewer attention directly back to the uncluttered atmosphere beyond. The result can be seen as either an advertisement for nothing or a pitch for the splendor of the natural environment shared between nations, offering an alternate reading of the billboard lexicon."

"It captures the Northwest!" proclaimed George Northcroft, the friendly bigwig—a Harlem-born-and-raised Obama-appointed regional GSA administrator—who MCed last month's dedication of the new border facilities. "The art is the sky—it's the world around us!" he told me.

The bigwigs seemed to really like the art. For once, the Americans have out-eleganced the Canadians—the bad architecture of the Canadian building on the other side of the border has earned it the nickname the Starship Enterprise, and there's no obvious art to be found there. Non-Sign II is a blatant symbol of progressive governance—a post-­monument for a post-empire. I heard the word "thoughtful" six times during the ceremony before I stopped counting. The fact that Non-Sign is also a vanishing is something we'll be able to continue thinking about, long after it whizzes by, for years to come. recommended