When President Trump announced his plans to build a border wall, “it felt a little like divine intervention for me,” says Brian Johnson, the principal of Collaborative Design Architects, a small firm in Billings, Montana. Johnson had already been sketching ideas for a border wall that resembled a series of hydroelectric dams, with curved concrete surfaces to foil climbers and a roadway on top for border-patrol vehicles. After Trump’s announcement, Johnson began refining the idea in anticipation of an RFP. He says, “I knew I had developed something capable of being more than just a wall.”

But where Johnson saw opportunity, many other architects felt outrage. “A border wall is just the wrong thing to do,” says Larry Strain of Siegel & Strain Architects in Emeryville, California. “It doesn’t make us safer, it doesn’t protect our jobs, and it is divisive rather than inclusive.” In early March, he and the members of his firm signed a pledge not to participate in the project, although, he says, they’d be happy to design a seat or a gate with the word bienvenidos.

The pledge was written by an advocacy group called the Architecture Lobby, which asked architects to walk off the job on Friday, March 10, to protest the RFP. Among the firms that complied was makeArchitecture of Chicago. According to its director, William Huchting, the six members of the firm stepped outside to discuss their problems with the wall, including its cost and the possible effect on immigrant communities, such as Chicago’s Little Village. “Hardworking immigrants have transformed 26th Street into the most vibrant shopping district outside of Michigan Avenue,” said Huchting. “We fear that this and other thriving neighborhoods will suffer if the wall is built.”

The border wall has been arousing controversy among architects since Trump first proposed it while running for President. After he was elected, an AIA statement that architects were eager to work with the new administration—though it did not mention the wall—elicited angry responses from AIA members. Anger surged again February 24, when the government announced a presolicitation “for the design and build of several prototype wall structures in the vicinity of the U.S. border with Mexico.” The Department of Homeland Security, according to the announcement, anticipates “procuring concrete wall structures, nominally 30 feet tall, that will meet requirements for aesthetics, anti-climbing, and resistance to tampering or damage.” Full details would be included in an RFP, which, at press time, was expected to be released in March. (The timetable has been extended twice; DHS did not respond to e-mails seeking comment on the reason for the delays.) Initial proposals would be winnowed, with those on the short list asked to submit full proposals as early as May.

By mid-March, some 650 firms or individuals had registered on the government website as potential vendors. Most were engineering and construction companies. But there were also dozens of architecture firms.

Firms on the list have various motives for registering. Nicholas Gillock of Los Angeles– based Mertzel & Gillock Architects says, “We’re not advocates of the wall; we’re advocates of using this as a platform for discussion. We’re looking into organizing a countercompetition as social commentary.”

John Sanford, who runs a small firm in Tulsa, says, “I’m a supporter of the wall, but I’d like to see it benefit people on both sides.” He believes that could happen by using the wall as a base for a high-speed train from San Diego to Houston, or as a way of researching new construction techniques. But he adds that the wall could negatively impact his firm’s projects. “We have a lot of Mexican subs,” he said. “We have a really good relationship with many of them. It’s hard to find people who will work that hard.”

Wyly Brown, a partner in the Norwell, Massachusetts, firm Leupold Brown Goldbach Architects, said, “I put my name on the list to stay informed. I am against the wall.” Brown said that his firm is a subsidiary of a German company, “and we know what walls mean.”

Brown said that, because he is on the list of potential vendors, he has received phone calls and e-mails from subcontractors interested in working with him. Many are women- and minority-owned firms, aware of government set-aside rules that generally require “primes” to work with qualifying “subs.” Brown said he tells firms that contact him that he has no plans to actually build the wall. But he doesn’t judge them. “There’s a lot of money involved,” he says. “It’s hard to say no to that.”