PORTSMOUTH — The City Council this week voted to indefinitely postpone third reading of a proposed zoning amendment that would regulate the size of political signs on private property.

The council voted to postpone any action on third reading on the recommendation of City Attorney Robert Sullivan, who said the city had been contacted by the American Civil Liberties Union of New Hampshire, which raised concerns that the proposed amendment could violate the First Amendment’s free speech guarantees.

Sullivan stated in a memo to City Manager John Bohenko that attorney Giles Bissonnette of the N.H. ACLU contacted the city about the proposed amendment.

“NHACLU has raised a number of potential issues regarding the constitutionality of the ordinance,” Sullivan said. “These concerns arise under the First Amendment, primarily due to the suggestion that the amendments as drafted may impermissibly regulate the content of signs. This would particularly be true in the case of political signs, where First Amendment analysis is conducted with heightened intensity.”

The main concerns Bissonnette raised include his belief that sign restrictions may “strongly impair the free flow of protected speech” and ideological speech may be entitled to greater First Amendment protection than commercial speech, but the proposed ordinance might do the reverse, Sullivan said.

The proposed zoning amendment, which the City Council passed two weeks ago, would regulate political signs from 120 days before an election to 14 days after.

The ordinance was drafted by the Planning Department in response to a recent U.S. Supreme Court decision regarding “content neutrality,” according to City Planning Director Juliet Walker.

“In the case Reed et al. v. Town of Gilbert, Arizona, et al. (2015), the U.S. Supreme Court ruled that regulations that categorize signs based on the type of information they convey and then apply different standards to each category are content-based regulations of speech and are not allowed under the First Amendment protections of the United States Constitution,” Walker said in an memo to Bohenko “Additional changes include updating the regulations regarding prohibited signs and temporary signs, clarifying sign area, and other housekeeping amendments.”

Several people raised concerns that the proposed amendment violated free speech guarantees when it passed second reading two weeks ago, and several other people expressed similar concerns Monday night during the council meeting.

City Councilor Chris Dwyer pointed out at the meeting “that cities and towns all over the country are struggling to deal with this Supreme Court ruling.”

“It seems like the concept of temporary signs, will essentially be gone,” she said.

She pointed to the city’s controversial protected bike lane on Middle Street and stated, “I guess for people who are offended by bollards the idea of sign proliferation all over town is probably inevitable.”

She then asked Sullivan “is that a correct interpretation?”

Sullivan replied that he and Walker don’t have “quite as morbid of an outlook.”

He stated city officials disagree with the N.H. ACLU’s view that “because political signs by their nature are temporary, and therefore any regulation of temporary signs” would impermissibly regulate political signs differently” than other signs

Sullivan noted, for example, that temporary signs could be used to sell cars.

“The fact that it’s temporary doesn’t mean it’s not content neutral is our view,” Sullivan said.

City officials, who have “a very good working relationship with the New Hampshire Civil Liberties Union,” plan to meet to try to address their concerns, Sullivan said.

The vote to postpone third reading gives city officials “a chance to meet with Mr. Bissonnette and go over our view compared to his view and see if we can resolve these things in an amicable fashion,” Sullivan said.

That may lead, he said, to “minor amendments” to the proposed ordinance amendment at third reading.

“We are not taking the position that means temporary sign ordinance regulations are dead,” Sullivan said.