Orleans Parish District Attorney Leon Cannizzaro found himself automatically re-elected to office Wednesday when the Louisiana Supreme Court ruled that his only challenger is not eligible to run for the seat.

The ruling, which drew a dissent from at least one justice, came as somewhat of a surprise after a winding legal case.

A trial judge initially tossed Cannizzaro’s opponent, Lionel “Lon” Burns, from the race for failing to show that he had filed all the necessary tax returns, then reversed herself after hearing testimony from his tax preparer.

Finally, in an opinion that turned mainly on the definition of the word “filed,” the state Supreme Court went against both the trial judge and the 4th Circuit Court of Appeal, disqualifying Burns and handing Cannizzaro another six-year term.

“The Supreme Court’s ruling puts this issue to rest once and for all,” Cannizzaro said in a written statement. “I am looking forward to moving from this campaign and focusing 100 percent of my time and attention to addressing the criminal justice issues that are facing this city.”

Burns called Cannizzaro to congratulate him shortly after the ruling came down.

Cannizzaro faces a myriad of criminal justice issues at the start of his new term. He has been a critical component of the strategy that Mayor Mitch Landrieu has put in place to cut the city’s murder rate, which includes targeting gangs with sweeping, multiple-defendant indictments.

And even though the number of murders has dropped significantly over the past couple of years, rates of other crimes remain stubbornly high. The city’s last roundup of statistics showed every category of major crime aside from murder rose in the first half of 2014, compared with the same six months of 2013.

Still, law enforcement officials in New Orleans have enjoyed relatively high job approval ratings recently — Cannizzaro included.

University of New Orleans professor Ed Chervenak, whose last survey pegged Cannizzaro’s approval rating at 55 percent, said the DA was headed for an easy re-election victory in any case.

Like the mayor, Chervenak said, Cannizzaro likely benefits from comparisons to his predecessor, Eddie Jordan, who resigned in 2007 amid a widespread perception of failure.

“He’s been more willing to cooperate with the police, more willing to take crimes to trial and more willing to work with the feds,” Chervenak said of Cannizzaro.

Burns, a defense attorney and former prosecutor, would have had only a short time to build name recognition, and he faced other challenges that might have proved a distraction, including a lien for back taxes.

His candidacy drew a legal challenge from Anthony Russo, a former Criminal District Court magistrate commissioner. Russo is a friend of Cannizzaro’s, and Burns accused the DA of using hardball tactics to try to drive him from the race.

Cannizzaro never directly acknowledged asking Russo to file the lawsuit. But one of his top assistants, Graymond Martin, filed the original request with the state Revenue Department asking for Burns’ tax records. Another assistant DA, Christopher Bowman, followed the lawsuit closely, even consulting with Russo’s attorneys during one hearing.

Initially, Civil District Court Judge Tiffany Chase ruled in Russo’s favor, denying Burns an extra day to call his tax preparer to the stand after a one-day trial on whether he had filed all his state and federal tax returns for the past five years, as required by law. But the 4th Circuit Court of Appeal ruled that Burns should be given the extra time.

After hearing testimony from the tax preparer, Monica Jackson, the judge reversed her original decision, ruling that Burns had filed his taxes to the “best of his knowledge,” having hired Jackson to prepare previously unfiled returns for 2010 through 2013. Jackson testified that she dropped off the returns at a post office on Louisiana Avenue.

Chase’s decision survived another appeal to the 4th Circuit.

But the Supreme Court ruled that both lower courts overlooked language in state law that spells out when tax returns should actually be considered “filed.” The law says they are not technically filed until they have been “delivered by the United States Postal Service” to the Department of Revenue. A state employee testified at the original trial that the department had not received tax filings from Burns since 2009.

The Supreme Court opinion did not specify an author, but Chief Justice Bernette Johnson signed a dissenting opinion.

Johnson pointed out that court precedent generally favors allowing candidates to run when their eligibility is questioned, in order to give voters the greatest number of options. She also disagreed with her colleagues about whether Burns needed to actually file his tax returns or simply believe that he did.

“The majority’s interpretation of” state law, she wrote, “would mean that Mr. Burns must ensure delivery and essentially perform the job of the U.S. Postal Service. Mr. Burns clearly exercised his reasonable best efforts to file his tax returns prior to qualifying for office.”