As recently as 2007, Mr. Flores, the former Webb County sheriff, was sounding the alarm over possible spillover violence from Mexico’s drug war. That year, Mr. Flores went head to head with Representative Henry Cuellar, Democrat of Laredo, on CNN, questioning the congressman’s loyalty to the United States and suggesting that Mr. Cuellar was more dedicated to Mexico’s president, Felipe Calderón, than to his own constituents. The move angered local lawmakers and business leaders, who said Mr. Flores was using the carnage in Mexico — and specifically in Laredo’s sister city, Nuevo Laredo, Tamaulipas — to paint the entire region as a hyperviolent war zone. In 2008, Mr. Flores lost his bid for re-election by fewer than 50 votes out of more than 26,000 votes cast, following a primary, a runoff, a recount and a theatrical election contest in which lawyers subpoenaed voters and asked them how they had cast their ballots. The victor was the congressman’s younger brother, Martin Cuellar, a former lieutenant with the Texas Department of Public Safety. The Cuellar family’s power made the city a tough place for Mr. Flores to live, he said. He moved to Arizona and worked briefly as the police chief in San Luis, then he failed to pass that state’s peace officer licensing exams. He made his way back to Laredo, where he is now running to reclaim his old job. Gone are the legions of support and the six-digit campaign coffers Mr. Flores had in the past. But the sound and the fury of old-school, border-style politics remain intact. “I am a person who’s relentless, and I don’t give up easily,” Mr. Flores said. “For me to just pack up my bags and leave like a coward, it’s just not my style, so I decided to come back and fight for what I left behind.” The Cuellar campaign says it is not worried about the November election. Mr. Flores is running as an independent in a Democratic stronghold, the result of the Webb County Democratic Party’s ruling that Mr. Flores had violated residency requirements and could not run as a Democrat. Mr. Flores said the ruling was an effort to squash the competition, and he blames the current sheriff for that. “What is he scared of?” Mr. Flores asked. In an affluent neighborhood next to the Laredo Country Club on a recent afternoon, Sheriff Cuellar sat under studio lights blotting his forehead while his campaign manager, Colin Strother, who also works for Henry Cuellar, coached the sheriff on how to deliver lines for a television ad. “Again, talk about the helicopter. Talk about how it is not costing taxpayers money,” Mr. Strother said. As the camera crew finished up, the mere mention of Mr. Flores sent the mild-mannered sheriff into attack mode. “He is such an idiot, man. And you can put that on the record,” Sheriff Cuellar said. Sheriff Cuellar said he had had nothing to do with Mr. Flores not being able to run as a Democrat. “I don’t make the rules. Especially election rules,” he said. Mr. Strother added that in order to be on the ballot, a candidate had to live in the county for a full year ahead of an election, and that Mr. Flores’s own interviews with the Arizona news media suggested that he had not made it back to Texas in time. Mr. Flores’s placement on the ballot as an independent was also a matter of contention. County officials in late August granted him permission to run, but only after roughly 300 of the 861 signatures on his petition were deemed ineligible. At least 500 valid signatures are required to get on the ballot as an independent. “I have always been a Democrat,” Mr. Flores said. “What I feel is that my party pretty much abandoned me.”
