As the clock struck midnight on a recent Thursday, Katie Moffitt enjoyed what will be one of her last visits to an Iowa City bar during peak party hours - at least for a few months.

Celebrating the end of the school year and a friend's birthday, Moffitt, a 20-year-old University of Iowa student from Chicago, went dancing at Studio 13, located at 13 S. Linn St. in downtown Iowa City.

Starting June 1, it will be illegal for Moffitt and other people younger than 21 to be in Iowa City bars after 10 p.m.

She's not a fan of the so-called 21-only law, which she believes will push drinking to house parties that she considers less safe than a bar.

“If they are stumbling around drunk in a bar, police can pick them up, friends can pick them up, make sure they're OK,” Moffitt said. “If you're at a house, you can stumble in another room and end up dead, passed out ... seriously hurt.”

Iowa City's minimum bar-entry age has been 19. City Council members who voted for the new law said something had to be done to address what they and many UI administrators say is rampant binge and underage drinking in this college town.

UI President Sally Mason told the council that reducing accessibility would help.

“Simply put, more students consume more alcohol where and when it's easier to obtain,” she said.

Predictably, the council's action met stiff resistance from students, bar owners and some members of the community.

One of the arguments against the measure is that the people already had their say when they voted down a 21-only proposal in 2007.

The council acted on its own this time, but a petition has been submitted for another referendum, this one to repeal the council's vote. If the petition is validated, it would likely go to voters Nov. 2.

In response to the house party claim, Iowa City Police Sgt. Denise Brotherton said there have always been large house parties in Iowa City, and that will continue.

“Good thing with a party as opposed to a bar is we can shut a party down,” she said.

Brotherton noted that the law goes into effect when many younger students will be home for the summer, so there probably will not be many big, immediate changes to the party scene. Even when school starts up, people will still be drinking alcohol downtown and making bad decisions, she said, and officers will continue to focus on that regardless of someone's age.

Dave Carey owns the Fieldhouse, a 19-and-older bar at 111 E. College St. on the Pedestrian Mall. He also owns three 21-only establishments in downtown Iowa City and five other bars elsewhere.

He predicts a number of downtown bars will go out of business if the 21-only law stays in effect, although he believes his other bars will help him absorb any losses at the Fieldhouse. That's an argument that has been made before, and detractors say if a bar owner needs people younger than 21 to keep his business afloat, then that's a bad business model.

Carey called that line of thinking “a joke,” saying he doesn't rely on underage drinking, but 33 percent of the Fieldhouse's business comes from cover charges patrons pay to get in the door, with people younger than 21 paying more.

He said the Fieldhouse's rent is $15,000 a month, and he believes bars are the only tenants that can afford to rent the large downtown spaces.

“It will hurt everything, not just the bar business,” he said.

Jim Clayton, owner of the Soap Opera, 119 E. College St., a retail store a couple of doors down from the Fieldhouse, doesn't doubt that some bars will close. He believes, though, that rents will decrease and those spaces will be filled. It's supply and demand, he said.

“Landlords are not going to sit on empty buildings very long,” said Clayton, a 21-only supporter who is a member of the Iowa Alcoholic Beverages Commission.

Brett Thomas, owner of Studio 13, said his bar should be OK financially, but he believes the law will hurt the culture of downtown Iowa City. Studio 13 is a gay bar, and Thomas said it is a refuge of sorts for gay students new to town.

“We help them come into themselves,” he said.

The owners of bars that offer live music also have said they worry about what the law will mean for them.

Brian Gustafson, a 20-year-old UI student from Naperville, Ill., interviewed downtown on a recent night, said he'll end up drinking with his friends at their houses.

“I really don't think it's going to stop anything in Iowa City,” he said.

The city likely has until at least Nov. 2 to find out if he's right.

Photographer Julie Koehn contributed to this report.