Scores of “sanctuary” cities, counties and states for undocumented immigrants are vowing to defy President Donald Trump’s executive order, issued last month, that threatens to block their federal funding, even as they—along with construction-industry interests—struggle to determine exactly how the edict would affect funds already earmarked for local infrastructure projects or expected for future ones.

Santa Clara County, Calif., on Feb. 23 filed suit in federal district court in San Francisco, seeking a nationwide preliminary injunction to block federal agencies from withholding federal funds to those municipalities that won’t participate in the administration’s expanded federal immigration enforcement and deportation efforts. Trump spokesman Sean Spicer said agencies would “unapologetically enforce the law, no ifs, ands or buts.” The county, which includes Silicon Valley communities, charges that the Jan. 25 order is unconstitutional. San Francisco filed a similar suit earlier this month.

“We are seeking a preliminary injunction now to protect the county from the president’s willful disregard of the limits on his power imposed by the Constitution,” says County Counsel James Williams. He said the order has created fiscal and budgetary uncertainty that has put the county’s ability to function in peril. While much of its $1.7 billion in annual federal funding supports safety-net services, the money also is included in transportation, housing and community development projects. Work with a federal component includes an ongoing effort to replace deteriorating county bridges that date to the late 1920s.

Officials say the vaguely written order fails to clarify which federal funding is affected. “In some places, it refers to ‘federal funds.’ In others, it refers to ‘federal grants,’ ” says Williams. “The order is so vague that the county has no idea what it must do to avoid being deemed ineligible for federal funds and other unspecified enforcement actions,” says the suit. The county also claims the order sets up a process that would allow Attorney General Jeff Sessions and Secretary of Homeland Security John Kelly to decide which municipalities to target and the severity of penalties. “The President has attempted … both to take Congress’s spending power for himself, and to extend that power far beyond its constitutional limits,” the county says in its suit.

The U.S. Dept. of Transportation’s federal highway program is a reimbursement program, but it is unclear whether or how its funding would be affected. DOT also provides grants to states, which distribute the funds to cities and counties. But agency grant programs—such as FASTLANE, TIGER and New Starts for transit—could be targeted, says a Feb. 18 Politico article. A department spokesman did not respond to a request for comment, but many federal agencies are stymied. “We are curious, and a lot of people are anxious,” said one federal agency official who asked not to be identified because he is not authorized to speak for the agency.

Open the Books, a private database of government spending, in a February report said 106 sanctuary cities alone received $21.5 billion in federal grants and $4.23 billion in direct payments in fiscal 2016. California, Connecticut, New Mexico and Colorado are sanctuary states. Chicago’s housing authority received $650 million in direct payments and $109.6 million in grants in fiscal 2016, says the report. The Oakland agency received $270 million. Other federal disbursements included $7.8 million to Mesa, Ariz., for the Phoenix-Mesa Gateway airport. Miami-Dade County dropped its sanctuary protections on Feb. 17 for fear it could lose millions of dollars for public transit projects, say published reports. But after the Trump order was announced, Cincinnati Mayor John Cranley (D) declared the city a sanctuary.

Industry groups are awaiting the details on project funding connections. “This is definitely an issue we are closely monitoring to see what federal officials ultimately opt to do,” says an Associated General Contractors spokesman.“It all depends on the guidance that comes out as a result of the order.”