HONOLULU (AP) – A new law allowing police and other authorities to ban people from public property for up to a year without a specific reason is unconstitutional, the American Civil Liberties Union said in a federal lawsuit.

The law could potentially be used to keep voters out of polling places or bar groups such as native Hawaiians from the grounds of the state Capitol, thereby chilling their constitutional rights to free speech, the ACLU said.

The law, known as Act 50, prohibits a person or group from entering a public building, park or other public place for up to one year after a warning or request to leave the premises has been issued.

It was aimed at removing squatters from public campgrounds, parks, beaches and other public places where they illegally put up tents and other temporary shelters. Under the law, those who “knowingly enter or remain unlawfully” on premises after “a reasonable warning” face charges of second-degree trespass, a petty misdemeanor, except in cases where actions are protected under federal labor laws.

In its lawsuit, the ACLU of Hawaii said Act 50 is too broad and is being used by authorities to restrict free speech by banning people from public places. The lawsuit asks the U.S. District Court in Honolulu to strike down the law and prevent officials from further enforcing the act.

Attorney General Mark Bennett, who along with Gov. Linda Lingle was named as a defendant, said the state would “vigorously defend” the law. He said the ACLU’s lawsuit is based on the flawed premise that authorities would abuse the law.

“Basically, every law is capable of being abused if you have an official whose goal is to abuse it,” Bennett said. “But just because a statute is capable of being abused doesn’t mean that the statute is unconstitutional. If you have those types of abuses you deal with them on an individual basis.”

The legislation was passed 47-0 in the House and 21-0 in the Senate this year and signed into law by Lingle on May 4.

The ACLU contends there are no standards or procedures for issuing a warning and no way for someone to appeal, adding that the law potentially could be applied to almost any situation.

For example, the lawsuit said, a police officer could stop someone from filing a lawsuit in court, a lifeguard could ban environmentalists from a beach, elections officials could prevent Democrats from entering voting areas such as public schools, and government officials could bar native Hawaiians from the grounds of the state Capitol and Iolani Palace.

Under the law, “it is enough that the police officer or authorized person finds the individual to be unsavory or disagrees with the content or message of the individual’s speech or activity,” the lawsuit said.

Lois Perrin, legal director for the ACLU of Hawaii, called the law “blatantly unconstitutional.”

“It’s a dangerous law and it should be stricken,” she said.

Bennett noted that there are many legitimate reasons – such as threatening or harassing – why authorities might seek to bar someone from public property, adding that those who feel they are being wrongfully silenced can sue.

“The fact that the statute could be abused if someone wanted to abuse it is a reason to try and prevent the abuse in individual cases, but not a reason to have the statute as a whole declared unconstitutional,” Bennett said.

The ACLU’s lawsuit was filed on behalf of Carlos Hernandez, a Honolulu man who said he was banned from the Hawaii State Library for a year for using its computers to access a GLBT website; and The Center, a nonprofit organization that provides programs and services for the local GLBT community.

Hernandez was using a computer at the library on May 18 when a security guard issued a written warning telling him he was being banned for one year because he was viewing a pornographic website, according to the lawsuit.

Hernandez and the Center say the website is not a pornographic site, but a resource with information on events, travel, real estate and other services for the GLBT community.

The lawsuit said Hernandez was not causing any disturbance and was issued the warning by a security guard who used his “personal discretion” to ban him from the library.

The Center complained on behalf of Hernandez and another person who was issued a warning, and was told by a library official that the security guard issued the warning because the website contained photos of men without shirts, the lawsuit said.