I fell in love with Elizabeth Diller, Ricardo Scofidio, AIA, and Charles Renfro, AIA, in the mid-1990s, when Diller and Scofidio lived, and all three of them worked, in a wondrously ramshackle studio above the Village Voice building in New York’s Cooper Square. (Renfro’s name wasn’t on the letterhead yet; at the time, he was the office factotum, the standout among a handful of smart employees and interns.) The whole setup—the exposed steampipes, the thoughtful, soft-spoken couple, their young, hip staff—perfectly matched my mental picture of bohemia. Then there was the work itself, which simply blew my mind.

Most emerging practices establish a reputation through house additions, apartment renovations, and store makeovers. But Diller and Scofidio took a decidedly different path. For the first decade or so of their collaboration, they produced conceptual projects, stage sets, and public art installations, all of which were pointedly polemical.

If there was a dominant theme in Diller and Scofidio’s early work, it was surveillance. Consider, for instance, the 1989 Para-Site installation at the Museum of Modern Art (MoMA) in New York, in which monitors displayed feeds from cameras in other locations throughout the building: bald pates and big hair spinning though the revolving front door, waistlines of every imaginable diameter descending an escalator. It’s all voyeuristic fun until you realize you can be watched, too—and then it gets creepy, fast.

Diller and Scofidio’s concerns about the intrusiveness of closed-circuit television might seem quaint by today’s standards. But who could have imagined, back then, that the federal government would be monitoring trillions of private emails and cellphone conversations each year?

The threats are frighteningly real, but all the surveillance in the world can’t guarantee our safety. Domestic terrorism—Newtown, Conn., the Boston Marathon—is growing tragically commonplace. Last October, in a speech at the annual meeting of the International Association of Chiefs of Police, U.S. Attorney General Eric Holder observed that mass shootings in the United States have tripled in frequency since 2009. On the very same day, a 12-year-old brought a Ruger 9mm semi-automatic pistol to his middle school near Reno, Nev., shot and killed a teacher, wounded two other students, and then killed himself.

Well before September 11, Diller and Scofidio exposed the devil in any exchange of privacy and other rights for a sense of protection. Such deals come with no guarantees, and are often ineffectual anyway. In January, Politico Magazine published an eye-popping essay by a former TSA agent confirming the limited utility of those onerous airport checkpoint procedures. The pat-downs, body scans, bans on liquids and gels, and removal of shoes and belts amount to security theater—a placebo ritual enacted to make us feel secure, even though it does not, in fact, make us safer. But it does sound like the premise for another one of Diller and Scofidio’s installations.

Diller Scofidio + Renfro has come under another kind of scrutiny recently, due to the firm’s involvement in the latest expansion of MoMA, which controversially will entail the demolition of the former American Folk Art Museum building designed by Tod Williams, FAIA, and Billie Tsien, AIA. It’s a damn shame to lose such a fine piece of architecture, and all the more so because it is uncertain whether a Diller Scofidio + Renfro–designed expansion will ever get built or, if it is, whether it will be built to the architects’ specifications. MoMA is a notoriously tricky client.

But if Diller Scofidio + Renfro does hold on to the job, I hope the firm will channel the spirit of self-awareness and criticality that made Para-Site so powerful. Because, unlike a transatlantic flight, a trip to a contemporary art museum should be a little unsettling.