The American Civil Liberties Union sent a letter to Jefferson Parish Councilman Ben Zahn on Monday saying that the parish’s annual holiday festival cannot ban or exclude any religious expression if another religion is promoted.

The letter was prompted by comments Zahn made Friday, when his office announced the annual holiday event at Lafreniere Park is now going to be called Christmas in the Park.

In an interview with The New Orleans Advocate, Zahn said that although he felt it was important to put the word “Christmas” in the title, the event was nevertheless open to all religions “within reason.”

Asked to clarify, Zahn, who had previously mentioned recent attacks by the terrorist group known as the Islamic State, said he meant that group, for example, couldn’t be represented in the event.

That statement brought Zahn some grief over the weekend, and he said his reference to the terrorist group was misinterpreted by people who thought it applied to Islam in general.

The ACLU took note of that discrepancy in its letter.

“Your statement that symbols related to the Islamic State are not welcome confuses politics with religion, because the Islamic State is not, in itself, a religion,” wrote Marjorie Esman, executive director of the Louisiana chapter of the ACLU.

Esman said in an interview Monday that, setting that issue aside, it’s “unthinkable” that an elected official would consider it is up to the government to decide what is and isn’t “within reason” when it comes to religion.

“This is elementary school stuff that you learn, that the government doesn’t get to decide what religion is legitimate and what religion is not,” she said, adding that Wiccans, Hindus and others get the same level of protection under the U.S. Constitution, regardless of their numbers or what elected officials think of their beliefs or their relevance.

As for the event’s name change, Esman said the legality of such matters depends on the specifics but that, generally speaking, singling out one religion’s holiday more than others “sends a message that they are at least suggesting that one religion has more value than others.”

Zahn’s office noted Friday that there is a Star of David, a Jewish symbol, among the lighted displays, but Esman said that’s what makes the celebration a holiday event rather than a Christmas event.

Renaming the event is telling people of other faiths “that their belief doesn’t count as much,” she said.

Zahn, whose district includes Lafreniere Park, declined to discuss the matter further Monday, standing by his contention that Christmas in the Park is still an inclusive event.

He said he believes his views were distorted in last week’s article because a paraphrased version of his reference to “ISIS” was changed to “the Islamic State,” in accordance with The Advocate’s style.

A spokeswoman for the parish administration referred questions about the ACLU letter to Zahn’s office.

Follow Chad Calder on Twitter, @Chad_Calder.