Louisiana’s successful charter school system, once it weathers an absurd lawsuit that ought to be decided in its favor on May 15, now has former U.S. Sen. Mary Landrieu on its side as a professional adviser as it builds on its considerable strengths.

Landrieu has a paid gig as a “strategic consultant” for the Walton Foundation, which supports charter schools — just as she did throughout her Senate career. (She also recently was named to the board of the National Alliance for Public Charter Schools, a notably bipartisan group.)

This is good news because, as Louisianians know, Landrieu can be a passionate and effective advocate, especially on issues that cross ideological lines.

More on Landrieu momentarily. First, let’s dismiss with the lawsuit — which is exactly what Judge Wilson Fields, of Louisiana’s 19th Judicial District, should do.

As I’ve written before, the lawsuit, which also puts at risk the Louisiana School for Math, Science, and the Arts along with the New Orleans Center for Creative Arts (among others), is meritless.

The suit (by the Louisiana Association of Educators union and the Iberville Parish School Board) attempts to stop the state education department and state school board from financing one type of charter school through the state’s Minimum Foundation Program, which guarantees baseline financing for public schools.

The same state constitution that says the MFP must be distributed through state and local public school boards also gives the state Board of Elementary and Secondary Education broad power to define what qualifies as such a school board. The charters at issue are indisputably public schools — students pay no tuition, the schools abide by desegregation orders, they take state-mandated tests and report audits to the state, etcetera — and there is no good reason for BESE not to use state public-school funds to finance them.

A key line from one of the briefs defending the current arrangement notes that the union and parish “want the MFP funds for students they don’t educate nor provide any educational services.”

To repeat: absurd.

As public policy, charters are working wonders. Without commenting on the specifics of the lawsuit, Landrieu made a compelling case that anything undermining charters will also undermine and perhaps reverse some remarkable progress.

“Many of the charters are absolutely proving, beyond a shadow of a doubt, that if you put children in the right schools with the right teachers and right leaders, you can change the status quo of mediocre and failing public schools,” she told me. “I’m all about disrupting the status quo when it’s not working. There are very few places in the country that can point to traditional public schools in the 1920 or 1930 model that are working in 2015 for poor and disadvantaged kids.

“Also, despite some heroic efforts to integrate schools, most Southern states still have segregated school systems, with public schools being mostly African-American and private schools mostly white. Charters have shown … the ability to truly diversify our system (voluntarily) by attracting middle-class kids of all races back into the public system.”

Landrieu cited numerous statistics demonstrating the success of charter schools, with New Orleans serving as a sort of laboratory model:

“In New Orleans, 95 percent of our public schools are charters. We’ve gone from 62 percent in 2005 (before widespread charters) who were attending failing schools to just 7 percent now. And New Orleans has out-performed the rest of the state among African-American students, with 59 percent scoring at least ‘basic’ level compared to the state’s 54 percent average. New Orleans in 2005 was scoring 67th of our state’s 68 districts; now it’s up to 41st of 69.

“The graduation rate has increased from 54 percent to 73 percent. Most dramatically, New Orleans outperforms the rest of the nation, with 65 percent of our black males graduating on time.”

That was just a sample of the highly persuasive numbers Landrieu cited. Likewise, she mentioned terrific charter success stories in rural Louisiana, too, especially Avoyelles and Union parishes.

Landrieu, to her credit, is right: With charter schools encouraging competition and innovation, Louisiana can become a leader in education.

For reasons both practical and legal, no lawsuit should stand in the way.

New Orleans native Quin Hillyer is a contributing editor for National Review. You can follow him on Twitter, @Quin Hillyer. His email address is qhillyer@theadvocate.com, and he blogs at blogs. theadvocate.com/quin-essential.