(Reuters) - The U.S. Supreme Court agreed on Monday to hear a conservative group’s free speech challenge to a Minnesota law prohibiting voters from wearing T-shirts or other apparel adorned with overtly political messages inside polling stations.

The U.S. Supreme Court building seen in Washington May 20, 2009. REUTERS/Molly Riley

A group called the Minnesota Voters Alliance is appealing a lower court’s decision to uphold the law, which forbids political badges, buttons or other insignia inside polling places during primary or general elections. State election officials have interpreted the law as also barring campaign literature and material from groups with political views such as the conservative Tea Party movement or the liberal MoveOn.org.

Violators are asked to cover up or remove offending items, but officials are instructed not to bar anyone from voting.

The Minnesota Voters Alliance, a St. Paul-based group that says it seeks to expose voter fraud, and several other organizations sued in 2010 claiming state officials turned polling places into “speech-free zones,” violating the U.S. Constitution’s First Amendment protection of freedom of speech.

Other states including Texas, New Jersey and Delaware have regulations similar to Minnesota’s, according to court filings.

The group’s executive director, Andrew Cilek, was temporarily prevented from voting for wearing a T-shirt bearing the Tea Party logo and a button that stated, “Please I.D. Me.” The button was part of a campaign opposing the state’s lack of a photo identification requirement for voting, court papers said.

In rulings in 2013 and 2017, the 8th U.S. Circuit Court of Appeals in St. Louis upheld the Minnesota restrictions, suggesting the law helps maintain “peace, order and decorum” at polling sites.

The plaintiffs, represented by the Pacific Legal Foundation conservative legal group, appealed to the Supreme Court saying a total ban on political speech unrelated to candidates or ballot initiatives is overly broad. The high court has allowed states to ban campaign materials and active vote solicitation at polling places, but not all political speech, the plaintiffs said.

“The Supreme Court’s decision to hear the case is a good sign for First Amendment rights,” foundation lawyer Wen Fa said in an email.

A spokesman for Minnesota Secretary of State Steve Simon declined to comment but state officials said in legal papers the law is neutral with respect to individuals’ viewpoints.

It was one of two cases the conservative-majority court took up on Monday in which conservative organizations are seeking to vindicate what they consider to be their free speech rights. The other involved a challenge to a California law regarding private facilities that counsel pregnant women against abortion.