One of them is Guadalupe Ochoa, 75, who owns a home near the redevelopment area. “We had voted for Mr. Beto, and now that he got to the top, and close to the power, he turned things around on us,” Ms. Ochoa said through an interpreter, Dr. Romo.

Mr. Cruz and the super PAC that supports him have seized on that chapter of Mr. O’Rourke’s career to attack him as elitist, accusing him in ads of “displacing poor families to enrich his own,” something that never happened — the plan itself was ultimately abandoned.

Mr. O’Rourke declined requests to be interviewed for this article. In response to claims that he favored developers over barrio residents, he has said in the past that he never voted for eminent domain, that no property was ever taken by the city through eminent domain and that he had no financial interest in the project.

Despite the resentment among some over the development plan, Mr. O’Rourke has broad support in his home city, where 80 percent of the residents are Hispanic but still regard Mr. O’Rourke, who is white, as a favorite son. “Beto” signs, T-shirts and lapel buttons are everywhere. Even many who objected to Mr. O’Rourke’s support for the redevelopment plan say they will vote for him.

Once a bustling city with 50,000 manufacturing jobs — and nicknamed the jeans capital of the world for its thriving garment industry — El Paso was hit hard by the North American Free Trade Agreement. As jobs moved to Mexico in the 1990s, the city’s strong retail trade also declined.

Mr. O’Rourke’s father-in-law, Mr. Sanders, now 77, had grown up in El Paso, attended Cornell, then started the national real estate company LaSalle Partners, headquartered in Chicago. The firm later merged with another to form Jones Lang LaSalle.