A county voter heads in to cast his ballot at a Tucson polling place in Tucson. The Supreme Court on Nov. 7, 2016, rejected a legal challenge to the city's election method.

Tucson's unusual method of electing council members will remain.

The U.S. Supreme Court this morning rebuffed a bid by a group representing Republican interests to void the system of nominating council members by ward but having them elected at large. The justices gave no reason for their ruling.

This morning's action is the last word in the multi-year bid by the Public Integrity Alliance to have state and federal courts declare that the practice was an unconstitutional violation of the Equal Protection Clause of the U.S. Constitution. They argued it effectively gave some voters more power than others.

But that contention was most recently rejected by the 9th U.S. Circuit Court of Appeals.

"Tucson's hybrid system for electing members of its city council imposes no constitutionally significant burden on voters rights to vote,'' the appellate court concluded. "And Tucson has advanced a valid, sufficiently important interest to justify its choice of electoral system.''

Attorney Kory Langhofer who represented challengers charged that the practice illegally disenfranchises residents of any five particular wards who have no voice on who advances from the other ward to a citywide general election. That system, he argued to the high court, gives the city "a nearly unfettered ability to deny the right to vote in the primary election.''

But there clearly was a partisan interest in the legal challenge.

Republicans hold a voter registration edge in one of the wards. But all six council members are Democrats, the result of the fact that they outnumber Republican on a citywide basis – the basis for the final council vote.

If the system had been voided and council members were elected by ward at the general election, that could have given Republicans a better chance of getting one or more members on the city's governing body.