Drawing upon his years undercover and his work in the private sector, Mr. Hurd has a starkly different vision for the southwestern border: fiber optic cables, sensors, radar, drones, increased staffing — but not the concrete or steel barrier that Mr. Trump has demanded before he reopens the government.

He has joined Democrats eight times this month to vote to reopen the government, without wall funding.

“Nobody likes being the cheese that’s standing alone,” Mr. Hurd said in an interview with The Daily, The New York Times’s podcast. “I have a unique perspective because I have so much border, because I have an entire career dealing with these issues. That is more important than any kind of political calculation.”