AUGUSTA – In September, Maine denied a Massachusetts distributor the right to sell three beers here.

The reason: The beers’ labels are “undignified or improper.”

The Maine Civil Liberties Union calls the denial censorship and a violation of the First Amendment, and is suing to prove it.

“The state doesn’t have the authority or justification to ban artistic speech like this,” said Zachary Heiden, a staff attorney with the MCLU who is working on the case. “The state of Maine consistently tries to do the right thing, and we’re certain they’ll try to do the right thing here. We’re just hoping to remind them of what the right thing is.”

Labels on three craft-brewed beers that Shelton Brothers Inc., a specialty beer distributor based in Belchertown, Mass., wants to sell in Maine, are at issue.

The label for “Santa’s Butt Winter Porter” features an illustration of Santa Clause sitting on a large barrel, also called a “butt.”

The second beer, “Les Sans Culottes” is illustrated with a detail from “Liberty Leading the People,” a painting by Eugene Delacroix, which hangs in the Louvre. The famous image shows a woman, dress ripped off the shoulders, waving the French flag and carrying a musket.

And the third beer is illustrated with a watercolor painting commissioned by a Belgian brewery for its “Rose de Gambrinus” beer. That painting depicts a nude woman sitting on the lap of a man.

Maine law requires beer and liquor distributors to register their labels with the Maine Bureau of Liquor Enforcement, which is responsible for making sure the labels are accurate, and obtain a certificate of approval.

A Sept. 20 letter from the state, the only reason given for the denial of the right to sell the three beers stated: “These labels are not being approved under Title 28-A This rule states ‘advertisements of liquor shall not contain any undignified or improper illustrations.”

Lt. Patrick Fleming, commander of the state police’s special investigations unit, which oversees liquor licensing, said he couldn’t comment specifically on the lawsuit because he hadn’t seen it, but he did describe some of the reasons a label might be rejected.

“In some cases, they might have inflammatory language or nudity,” Fleming said.

The rules, which are broadly written, also have a prohibition against labels that might target children, Fleming said. “If you have a minor going through the beer aisle, and they see Santa Claus sitting on a beer barrel, that might induce a minor to drink.”

According to Fleming, the state reviews between 10,000 and 12,000 labels a year and denies certification to maybe a dozen.

“We try to work with the people when we do deny them,” Fleming said. “And often we can suggest changes, and they can resubmit the labels.”

The Maine Civil Liberties Union filed the suit in U.S. District Court in Portland on Thursday, Heiden said.

“This is about artistic expression, and it’s about protecting our right to see art,” Heiden said. “Art is entitled to the highest level of First Amendment protection.”

A message left with Daniel Shelton of Shelton Brothers was not returned Thursday.

“These illustrations have been used on beer sold across the country,” Daniel Shelton told the MCLU for inclusion in its news release on the lawsuit. “I can’t imagine why Maine would object to Santa Claus.”

According to Heiden, the state has a legitimate interest in checking and approving the labels on beer to make sure they are accurate. But the state is not an appropriate judge of art.

In the case of Delacroix’s painting, which has been used on France’s 100-franc note, the argument can be made that it’s one of the most important pieces in French art history, Heiden said. “Thousands upon thousands of school children have seen this.”

“This is not some abstract question about freedom of expression,” Heiden said. “It’s really about the books we read, the art we see, the movies we see and the beer we drink.”