DALLAS, Texas — A Dallas suburb’s long, expensive fight to ban illegal immigrants from renting homes will get perhaps its most important hearing Wednesday before a largely conservative group of judges with the power to influence the national immigration debate.

Farmers Branch was sued four years ago after it passed an ordinance allowing the city building inspector to evict any illegal immigrant renters. Its case will now go before the full membership of the 5th U.S. Circuit Court of Appeals, with 10 judges appointed by Republican presidents and just five by Democrats.

So far, no court has allowed Farmers Branch to enforce any form of the ordinance. But the appeals court’s rare move to hear the case a second time, months after a different three-judge panel ruled against Farmers Branch, could be a sign that the town might finally get a victory.

The current ordinance, which replaced an earlier 2006 version, would require all renters to obtain a $5 city license and fill out an application that asks about their legal status. Then, the city’s building inspector would have to check whether any immigrant applying for a license was in the United States legally. Illegal immigrants would be denied a permit, and landlords who knowingly allow illegal immigrants to stay as tenants could be fined or have their renters’ license barred.

The appeals court has directed all sides to focus on the U.S. Supreme Court’s June ruling on Arizona’s tough immigration law. That ruling rejected major parts of the law, but upheld the so-called “show me your papers” requirement, which gives law enforcement authority to check a person’s legal status if officers have reasonable suspicion he or she is in the U.S. illegally.

Farmers Branch’s attorneys argue that the city’s ordinance is substantially different from Arizona’s law and that the Supreme Court didn’t act to stop local officials from restricting illegal immigrant renters.

Attorneys for the landlords and renters who originally sued the town believe Farmers Branch is encroaching on legal territory reserved for federal authorities.

A federal district judge ruled against the city two years ago, and a three-judge panel at the 5th Circuit upheld that ruling in March.

Nina Perales, vice president of litigation for the Latino civil-rights group MALDEF, said she believed local officials could communicate with federal authorities on immigration matters, as long as they didn’t take action on their own.

“Where the Supreme Court has drawn the line is where state and localities are taking unilateral adverse action against people they think are undocumented,” said Perales, who will argue before the 5th Circuit on Wednesday.

Kansas Secretary of State Kris Kobach, a national advocate for tougher illegal immigration laws, will represent Farmers Branch before the full court, in what’s known as an en banc hearing. He said Tuesday he believed the Supreme Court upholding the “show me your papers” requirement strengthened Farmers Branch’s case.

“The fact that the en banc decision was granted in and of itself was a win for the city, getting the opportunity to make the case as to why the panel majority was wrong,” Kobach said.

The full 5th Circuit is generally considered to be one of the nation’s most conservative federal courts. Its decision to hear the Farmers Branch case is rare — fewer than 5 percent of petitions for a full court hearing are granted — though the court rehearing a case doesn’t necessarily mean judges intend to reverse an earlier decision.

Based in New Orleans, the 5th Circuit hears cases from Texas, Louisiana and Mississippi, and its rulings are binding in those states only. But other circuit courts are considering laws similar to the one passed by Farmers Branch, and one circuit’s opinion can be cited by attorneys elsewhere.

In August, a federal appeals court in Philadelphia heard arguments in a case from Hazleton, Pa., a former coal-mining town that also tried to ban illegal immigrant renters by requiring rental permits. The court has not yet ruled.

Farmers Branch has spent nearly $6 million on legal bills and expenses related to illegal immigration, according to a town spokesman.

Mayor Bill Glancy said in an interview that the town was not inhospitable to minorities, despite complaints from some Latinos that they feel targeted by police. Glancy pointed to English classes offered at the local library that attract dozens of people from different countries.

“They’re against illegal immigration,” Glancy said of his town’s residents. “They have supported legal immigration for a long time.”