New Orleans Mayor Mitch Landrieu signs an executive order adopting a climate action plan on the roof of the Sewerage and Water Board administration building in New Orleans, La. on Friday July 7, 2017.

Advocate staff photo by Jessica Williams

During the complicated transition between the outgoing Obama administration and the incoming Trump team, those who tried to adhere to traditional norms often referred to an unwritten rule: There's only one president at a time.

The upcoming New Orleans mayoral transition surely won't match the drama of what happened and continues to happen in Washington, but still, we might find ourselves having to repeat the mantra that there's only one mayor at a time. There's a real possibility that it won't feel that way.

With the close of qualifying to replace Mayor Mitch Landrieu this week, many eyes will be on his potential successors as they campaign for the October primary, with a November runoff if needed. Because the candidates will be seeking to replace an eight-year incumbent, they will inevitably focus on what type of change they hope to bring to City Hall.

That's what always happens during election season, but this year's quirky calendar will extend the in-between period for longer than usual. At the behest of the League of Women Voters and others who worried that winter elections can get overshadowed by the holidays, Mardi Gras and (in good years) football playoffs, the Legislature adopted an idea first envisioned in a charter change two decades earlie, and moved municipal elections back to the previous fall.

But because Landrieu was elected under the old calendar, he'll stay in office through May. That means his lame duck period could stretch more than six months.

And face it: Landrieu isn't exactly one to fade into the background. Indeed, when he won the election to succeed the tuned-out Ray Nagin, he quickly assumed the leadership mantle. That turned out to be a good thing on several fronts. City finances had reached a crisis point, and the BP oil spill happened before he was formally sworn in. Landrieu's people had to get right to work, and they did.

Landrieu's no Nagin, though.

He's made it clear he intends to finish strong and is still introducing new initiatives, such as the climate change policy he unveiled last week.

He will be speaking out on national issues even more than he has been, in his new role as president of the U.S. Conference of Mayors and with the newfound prominence he earned following his nuanced speech defending the removal of four Jim Crow-era monuments from city streets.

He's hinted that he hopes to help guide the choice of his successor, perhaps through the political action committee he has set up. While he hasn't endorsed a candidate, Landrieu has bemoaned New Orleans voters' history of focusing on change and has advocated for philosophical and policy continuity from his administration to the next.

And he's clearly not going to let his critics go unanswered. Just this week, he responded to comments U.S. Sen. John Kennedy made about crime in New Orleans, while quizzing Trump's nominee for new FBI director, with a scathing three-page letter defending his commitment and accusing Kennedy of using tragedy as a "political football."

"In my remaining 299 days in office, I will continue to focus on reducing violent crime," Landrieu wrote, continuing a countdown that he started way back in 2010.

As the campaign develops, those critics will likely include at least some of the candidates for mayor. They may well concede that Landrieu has left the city on a much more solid financial and ethical footing, but they're already concentrating on areas where problems persist, including violence, affordable housing and inequality.

On all these fronts, Landrieu will surely still have plenty to say right up until the end. But starting this week and for the next 10 months, he'll no longer have the microphone all to himself.

That could make the upcoming stretch unlike any period New Orleans politics has seen.

Follow Stephanie Grace on Twitter, @stephgracela.