LAFAYETTE — A group of downtown bar owners hopes to strike down a special security fee without a court fight, arguing on a technical issue that Lafayette city-parish government has failed to respond to their federal lawsuit by the legally required deadline.

The federal Clerk of Court’s Office on Tuesday put city-parish government on notice that it might lose the case by default for not responding to the lawsuit filed last year by Karma, the Rabbit Hole, Nite Town, Shakers and Guamas, which has since closed.

City-Parish Attorney Michael Hebert said via email that city-parish government will likely file court motions on Wednesday contesting the default judgment.

At issue in the lawsuit is a downtown security fee that the City-Parish Parish Council approved in 2009 — an effort to force bars to share in the increasing expense of special police details that keep weekend crowds along Jefferson Street in check.

The fee ranged from $150 to $5,000 a month per bar, depending on capacity, but the council in April voted to suspend the bar levy pending the outcome of the federal lawsuit.

Bar owners argue that the fee amounts to an unconstitutional tax imposed without their consent, and by the end 2011, several of the bars had stopped paying it.

The lawsuit was filed in January 2012, a few weeks after city-parish officials moved for liquor license suspensions of up to a year against bars that were refusing to pay the fee.

A default judgment against city-parish government in the lawsuit could automatically strike down the downtown security fee without any court hearings on its constitutionality.

The bar owners are also asking a judge for at least $75,000 in damages and the reimbursement of all fees paid since the security fee was imposed in 2009.

A federal judge would have to approve the default judgment and any damages.

The bar owners’ attorney, Daniel Stanford, argues in court filings for the default judgment that the legal deadline for city-parish government to respond to the lawsuit has long expired.

City-parish officials were formally served with the lawsuit on June 28, 2012, and a response to the lawsuit was due by July 19, Stanford said.

There is no indication in the court record that city-parish attorneys have filed anything in the case.

Hebert, the city-parish government attorney, said there are questions over whether the bar owners met the legal deadline to notify city-parish government after the lawsuit was filed, but he declined to elaborate.

While the litigation is pending, city-parish government continues to absorb an overtime expense of about $460,000 a year for the police details that keep watch over the busy downtown bar scene.

Councilman Brandon Shelvin, who represents the downtown area and opposed the bar levy, secured passage of the ordinance in April to suspend the fee until the bar owners’ lawsuit is resolved, but some council members have talked of revisiting the issue sooner.

Councilman Don Bertrand said Tuesday that he would like to explore some other way to fund the patrols.

“I’ve given it some thought, but there doesn’t seem to be a lot of interest in it,” Bertrand said.

He said he hopes the recent developments in the litigation might stir some discussion about the issue.