The U.S. Supreme Court on Monday said it will not consider In-N-Out Burger's attempt to stop workers from wearing buttons pushing for a higher minimum wage, rejecting a bid by the burger chain to broaden a ruling from last year that restricted the power of unions to collect fees from nonmembers.

In-N-Out Burger, represented by Littler Mendelson, asked the high court to overturn a federal appeals court decision striking down a workplace rule that prohibited employees from wearing insignia on their uniforms, including “Fight for 15” buttons.

The Supreme Court declined the petition without comment. The U.S. Justice Department, representing the National Labor Relations Board, had urged the court to turn down the petition for review.

The case before the high court stems from 2015, when employees at an In-N-Out Burger in Austin, Texas, wore “Fight for 15” pins on their uniforms. The company argued that its employees are subject to uniform rules that prohibit any type of pin or sticker.

The U.S. Court of Appeals for the Fifth Circuit upheld a National Labor Relations Board decision that said the rule violated the employee's rights to concerted speech. The appeals court noted that the restaurant chain requires its employees to wear company-issued buttons twice a year, one for Christmas holiday and another that solicits donations to the In-N-Out Foundation focusing on preventing child abuse and neglect.

In its petition to the high court, the California-based burger chain's attorneys cited the divided Supreme Court decision last year in Janus v. AFSCME, which said public-sector unions can't force the collection of so-called fair share fees from nonmembers. Littler Mendelson shareholder Bruce Sarchet in Sacramento said the NLRB was compelling an employer to endorse a pro-union message by allowing the buttons.

The U.S. Justice Department asked the Supreme Court to reject In-N-Out Burger's argument, saying that the lower courts need to examine the scope of Janus decision. State and federal courts are still exploring the reach of the decision in Janus.

“Indeed, lower courts have had just over six months to consider the scope of Janus, and few decisions have yet applied it outside the agency-fee context in which it arose. Further percolation on this issue is plainly warranted,” Noel Francisco, the U.S. solicitor general, wrote in a filing at the high court.

In the Janus case, the Justice Department had urged the justices to overturn decadesold precedent to rule that public-sector unions could not force nonmembers to pay “fair share fees.” The divided Supreme Court, led by Justice Samuel Alito Jr., concluded those fees violated the First Amendment speech rights of nonunion members.