New York Times

WASHINGTON — An extraordinary letter landed at the Supreme Court last month. In it, Illinois’s attorney general accused its governor of violating the law — by filing a brief at the court.

The accusation was but one salvo in the white-hot war over the fate of public unions, which hangs in the balance in a case to be argued early next year. It gave the court a taste of Illinois’s bruising politics and a sense of how closely the state’s officials, workers and unions are watching the case.

The contested brief, from Gov. Bruce Rauner, a Republican, said his state’s public unions “have negotiated wages and benefits that have unrealistically kept going up while the state economy has kept going down.”

The state’s attorney general, Lisa Madigan, a Democrat, was not happy to see the governor’s brief. Her top appellate lawyer wrote to the justices to alert them to “an unauthorized filing, purportedly on behalf of Bruce Rauner, governor of Illinois.”

“Neither the governor nor his attorneys have the authority, as a matter of state law, to represent the state or its officials in any court or to determine the state’s litigation positions,” the lawyer, Solicitor General Carolyn Shapiro, wrote.

As a purely legal matter, she seemed to have a point. The Illinois Supreme Court has said the state attorney general “is the chief legal officer of the state and the state government’s only legal representative in the courts.”

The governor’s general counsel, Jason Barclay, did not really contest the point in his own letter in response. The governor had not meant to speak for the state, Mr. Barclay wrote. Indeed, he said, the brief “makes very clear that it is filed only in his individual capacity.”

If there is support for that assertion in the brief, it is hard to find. The phrase “individual capacity,” for instance, does not appear in it.

The assertion in any event presented its own problems, Ms. Shapiro wrote in a third letter. “It would be unlawful,” she wrote, for “state employees paid from public revenues to represent Mr. Rauner in his individual capacity in any matter.”

Mr. Barclay clarified his position in an email on Friday. He now said the governor “filed the brief in his official capacity” but “was speaking on behalf of his office only.”

“The term ‘individual capacity’ in our letter to the court does not mean or imply ‘private citizen,’ ” Mr. Barclay wrote.

James E. Tierney, the director of the National State Attorneys General Program at Columbia Law School, said Ms. Shapiro had the better of the exchange in the dueling letters.

“The law in Illinois is clearly on the side of the attorney general,” he said.

The charges in Ms. Shapiro’s letters may be correct, then, but it is hard to see what they accomplish. She did not ask the Supreme Court to reject the governor’s brief. Indeed, she may have piqued the justices’ interest in it.

Neal E. Devins, a law professor at William & Mary, said the attorney general, or A.G., may have had a different audience in mind.

“Perhaps the A.G. wants to signal to home state constituents that the governor is lawless and is seeking political advantage by embarrassing him,” said Professor Devins, an author, with Saikrishna Prakash, of a recent article in The Yale Law Journal on the obligations of state attorneys general.

A.G., the article explained, is short for “aspiring governor.”

The issue in the case, Friedrichs v. California Teachers Association, No. 14-915, is whether public workers who choose not to join unions may be required to pay “fair share fees” to pay for collective bargaining.

“Forced union dues are a critical cog in the corrupt bargain that is crushing taxpayers,” Mr. Rauner said not long after he assumed office in January. “An employee who is forced to pay unfair share dues is being forced to fund political activity with which they disagree. That is a clear violation of First Amendment rights.”

If such compelled payments do violate the First Amendment, the Supreme Court has yet to say so. But it came close in 2014 in a case from Illinois,Harris v. Quinn.

The defendant was Pat Quinn, the Democrat who preceded Mr. Rauner as governor. Mr. Quinn, represented by the state’s attorney general, urged the court to reaffirm a 1977 decision that allowed public unions to collect fees from nonmembers for collective bargaining.

The Supreme Court, in a 5-to-4 decision, instead came close to overruling the 1977 decision, Abood v. Detroit Board of Education. The majority invited a fresh challenge, which arrived almost immediately, in the form of the Friedrichs case.

The new governor took a new position.

“Illinois is a poster child for why Abood should be overruled and all public-sector employees’ First Amendment rights restored,” Mr. Rauner wrote in a brief supporting teachers challenging California’s collective bargaining system.

There is nothing particularly unusual in a new administration’s shift in a legal position. Virginia opposed same-sex marriage in the Supreme Court in 2013 in a brief filed by a Republican attorney general and supported it in 2015 in a brief filed by a Democratic one.

What is unusual is confusion over who speaks for the state in the Supreme Court, said Michael A. Scodro, a lawyer with Jenner & Block who served as Illinois’s solicitor general from 2007 to 2014.

“Clarity on legal positions is essential for the state,” he said, “and the Illinois Constitution asks the state to speak with one voice in courts.”