(CNN) The Bible says we're all sinners. But does that mean a church should have its own police force?

A megachurch in Birmingham, Alabama, thinks so, and state lawmakers agree.

The Alabama Senate voted Tuesday to allow Briarwood Presbyterian Church to hire fully deputized officers who would carry weapons and have the authority to make arrests.

A church-run police squad would be highly unusual. The ACLU even says it's unconstitutional.

But officials at the church, which also houses a school, say armed officers are needed to keep their flock safe in a volatile world.

"After the shooting at Sandy Hook (Elementary School) and in the wake of similar assaults at churches and schools, Briarwood recognized the need to provide qualified first responders to coordinate with local law enforcement who so heroically and effectively serve their communities," the church said in a statement provided to CNN.

'A safe environment'

Briarwood Presbyterian has a congregation of more than 4,000. Its giant complex also houses a K-12 school and a seminary.

The church says the purpose for the legislation is to provide "a safe environment for the church, its members, students and guests."

Alabama law does not prohibit someone from carrying a gun into a place of worship.

If the bill before the Alabama legislature becomes law, at least one expert believes Briarwood Presbyterian would become the only church in the nation to have its own police force.

Currently the Jefferson County Sheriff's Department responds to emergency calls for service to the church, and off-duty police officers from area law enforcement provide additional security for services and other church events.

The church said its "police officers would be restricted to the church's campuses and be able to respond to emergency situations while coordinating with local authorities."

But the ACLU of Alabama believes the bill would not survive a legal challenge if signed into law.

"We think it's plainly unconstitutional as per the establishment cause of the First Amendment," ACLU Attorney Randall Marshall said.

"These bills unnecessarily carve out special programs for religious organizations that inextricably intertwine state authority and power with church operations. We urge the legislation not to pass these unconstitutional bills," he added.

Marshall said the state legislature "often passes unconstitutional legislation" without regard for the expense of defending it in court. It's not unusual for legal fees to reach six figures, he said.

On to the House

Chuck Chadwick, founder and president of the National Organization of Church Security and Safety Management, says he is unaware of any church in the country with its own police. But he sees the benefit.

"I don't find it unusual that they would want to do this from a public safety standpoint," said Chadwick, who consults churches across the nation on their security plans.

He says that huge churches like Briarwood Presbyterian have sprawling campuses that could benefit from additional security.

The Alabama Senate passed the bill 24-4, and it will now head to the House. If passed there, the bill would be sent to newly minted Alabama Governor Kay Ivey's desk.

CNN has reached out to both sponsors of the legislation but has yet to hear back.