Updated Nov. 28: Revised with the Texas Supreme Court's decision Wednesday to allow the withdrawal of the amicus brief and details of a filing Wednesday by the city of Plano related to that brief.

For a moment, Attorney General Ken Paxton’s office appeared to be taking a righteous stand in Plano’s legal fight with residents over the city’s comprehensive development plan.

Until less than 24 hours later when the AG’s office offered a new opinion: Never mind.

In an unusual change of heart, Paxton’s legal team filed a motion Nov. 20 to withdraw an amicus curiae brief it had submitted just a day earlier to the Texas Supreme Court. The brief supported Plano's legal position.

All Paxton’s office will say about the brief is the few words contained in the filing — that it was “erroneously submitted.” I asked a spokeswoman to elaborate, and she replied by email, “The filing speaks for itself.”

If that’s the case, the attorney general’s operation doesn’t look too sharp.

I find it difficult to believe this brief was filed by accident, given the number of layers these kind of documents go through before sign-off. If, in fact, a document of this magnitude was inadvertently filed, how inept is that?

This fishy development is just the latest twist in a municipal lawsuit that has bedeviled Plano for almost three years.

The City Council approved the Plano Tomorrow master plan in October 2015 after what it described as a several-years-long listening tour involving thousands of residents. Leaders revised the plan at least twice to appease residents who were worried that it would lead to more apartments and big developments. Many of those residents loosely united under the label Plano Future.

Soon after the plan passed, Plano Future member Beth Carruth, now among the five lawsuit plaintiffs, submitted a petition with more than 4,000 signatures demanding the council repeal its action — or let voters decide Plano Tomorrow’s fate. The city secretary denied the document on the grounds that development plans such as Plano Tomorrow fall outside the bounds of referendum votes.

A drawn-out, costly lawsuit has ensued. Most recently, on Nov. 16, Plano filed a motion for a rehearing before the Texas Supreme Court. The city is asking for the court to rule that the city secretary is immune from legal action for performing her duties on the grounds that it believes state law prohibits comprehensive plans from being subject to referendum votes.

The following Monday, Paxton’s office filed a 17-page amicus brief with the court that supported Plano’s case, detailing the reasons the justices should grant the rehearing and “render judgment dismissing plaintiffs’ lawsuit.”

A long exposure shows traffic on the Dallas North Tollway at Tennyson Parkway with Legacy West, Liberty Mutual, and The Shops at Legacy development in Plano. (Smiley N. Pool / Staff Photographer)

The brief prepared by the attorney general’s office doesn’t just state its position but goes so far as to say that the appeals court got it wrong. The document bolsters Plano’s position by saying that state law controls issues such as referendums — and it cites 37 cases to back up that point of view.

The amicus brief goes on to argue that comprehensive plans indeed have been removed by the state from the power of referendum. The city secretary correctly identified that point, she is simply performing her legal responsibilities as a city secretary and she can’t be sued for that.

This is exactly what the city of Plano and its outside legal team, led by former Texas Supreme Court Chief Justice Wallace Jefferson, have argued all along. For one day, the attorney general’s office — an objective observer and not a party to this lawsuit — was saying the same thing.

As if this doesn’t smell bad enough, Republican precinct chair Matt Dixon made a bunch of concerning assertions about the process at the Plano City Council meeting Monday.

During the open comment segment, Dixon first accused Jefferson and the city attorney’s office of orchestrating the amicus process. “Was it Mr. Jefferson using his contacts at the AG’s office to get this through, which some people might consider influence peddling?” Dixon speculated.

Within hours of the brief being filed, Dixon said, a group of residents was alerted “to this scheme” and began contacting key people. Although Dixon didn’t specify who those people were, he said, “The result was that within 12 hours the attorney general had issued orders to withdraw the brief.”

Dixon’s long and gleeful statement indicated that he believes the residents’ political influence — not the law itself — led to this outcome. Paxton’s office did not respond to questions about Dixon’s remarks.

Plano Mayor Harry LaRosiliere said Tuesday night, "This unprecedented request by the attorney general — to withdraw an amicus brief filed by his office — signals that either playing politics or allowing severe error has interfered with the rule of law, something by which all Texans should be alarmed."

The Supreme Court on Wednesday granted the motion by Paxton's office to withdraw the supporting document.

Kyle Hawkins, the solicitor general in the attorney general’s office, first alerted Jefferson of the plan to withdraw the brief. Hawkins declined to share any details with Jefferson of why the change of heart.

Jefferson said withdrawing an amicus brief is an unusual — if not unprecedented — action, especially for a document as carefully researched and detailed as the one Paxton's office filed. I also ran that by Dallas lawyer Deborah Hankinson, who specializes in appellate issues and has a good bit of experience with how the attorney general’s amicus process works. She concurred, describing the attorney general’s move as “highly unusual.”

While the city of Plano didn’t have much choice but to accept the brief’s withdrawal, Jefferson and his legal team filed a response Wednesday that the Texas Supreme Court consider the legal arguments in the document, despite the fact that Paxton's office requested it be withdrawn.

The Plano Tomorrow lawsuit is a big deal far beyond this Collin County suburb. If visions for overall land use, created by democratically elected officials, can be overturned by referendum, cities all over North Texas could face disarray as development is stopped in its tracks.

That’s why, amid all the red flags around the attorney general office’s change of heart, it’s important to remember the content of the amicus brief.

The “erroneously submitted” excuse doesn’t imply that anything was wrong with the brief’s analysis of the Plano Tomorrow lawsuit. Whether something is amiss in the withdrawal of the document is a question to which the city of Plano deserves an answer.