A group of about 15 young men exited the Silver Spring Metro station on a recent Friday night, heading toward the area’s bustling open-air restaurant district.

Just before 10 p.m. they passed a police lieutenant. No hellos or smiles, but plenty of tattoos and stares.

“My hunch is that’s not a good crowd,” Montgomery County police Lt. Robert Carter said, calling into his radio to alert fellow officers to keep track of them.

For 38 minutes they watched. The group made its way to Dixon Avenue, a darkened street just off the main strip. Officers confronted them and started asking questions. Just a month earlier on those same streets, more than 50 young men, many of them gang members, got into nighttime brawls that lasted hours. When police chased them from one spot, the group gathered a few blocks away and kept fighting. By the end, a female had been stabbed.

That melee pushed Montgomery’s top elected official, County Executive Isiah Leggett (D), to propose a countywide curfew for ages 17 and younger: midnight on weekends, 11 p.m. during the week.

Police say that there’s been an uptick in arrests of juveniles and that a curfew law would give officers a valuable tool to head off trouble. Neighboring Prince George’s County and the District have curfews, which police say are pushing more youths into Montgomery late at night. Philadelphia officials recently toughened their teen curfew to tamp down on flash mobs.

But others in Montgomery say a curfew is an overreaction, wouldn’t be effective and — at its worst — could lead to racial profiling. Most crimes committed nationwide by young people don’t occur late at night, research has shown. The same holds true in Montgomery, where 92 percent of assaults and 83 percent of robberies for which juveniles were arrested last year happened outside the proposed curfew’s hours.

As the Montgomery County Council prepares to vote on the measure this fall, the debate is intensifying.

“Parents are divided on this issue between those who believe it is an unnecessary intrusion into how they raise their children and parents who believe it will make the community safer,” said council member Roger Berliner (D-Potomac-Bethesda), a curfew skeptic.

On Wednesday, Leggett proposed amendments to the bill to tone it down. Youths coming home from movies, concerts and sporting events would be exempted. Rather than detain curfew violators, the officers would issue a civil citation, punishable by a fine of up to $100 for the first offense. Then, if the kids don’t go, officers could arrest them for failing to obey a lawful order. Forcing parents of curfew violators to attend parenting classes is no longer part of the proposed curfew.

When officers approached the group on Dixon Avenue, the teenagers answered questions and had their pockets searched and their tattoos photographed. Police found no weapons or drugs and didn’t charge anyone.

“They just automatically assumed we were thugs, or we were about to cause some trouble or go fight,” said Mike Brown, 18, a James Hubert Blake High School student who ended his junior year with a 3.1 GPA and thinks the youths were targeted because they are black.

Carter said it was not about race. The officer had exchanged friendly hellos with other black teens that night, but this group was larger and passed by without a word. He said he “absolutely would have done the same thing” had the youths been white.

Although Brown didn’t like the way he and his friends were stopped, he’s not anti-curfew. He said he has seen some late-night fights in Silver Spring and thinks the curfew could help.

The proposed curfew is county-wide, but much of the debate has focused on downtown Silver Spring, a once lackluster stretch that has been transformed in recent years and now draws big crowds. This month, the Fillmore theater is scheduled to open and bring in even more people. As recent nighttime visits show, the streets are busy and friendly.

After 11 p.m. Friday, Guinean nanny Amina Traore, 23, emerged from Ramadan services at a nearby civic center wearing a black-and-white African gown. Her 3-year-old nephew ran up and down the closed-off street yelling, “I’m Spider-Man-Superman!

Two-year-old Bryanna Rodriguez spun in circles, licking vanilla ice cream that looked pink in the red-neon glow of Silver Spring’s Majestic theater. Bryan Rodriguez, 5, climbed into their younger brother, Bryseidy’s, stroller, lying back to get comfortable.

Their parents, Eudy Rodriguez and Yudi Arevalo, both 23, enjoy the downtown but don’t always feel secure.

Problems percolate when crowds surge with the pristine weather or during festivals, Rodriguez said, calling the curfew “100 percent a good idea.” Some young people “just make dramas for nothing, fighting,” Arevalo said.

Just before 1 a.m. Saturday, Yory Martinez, 17, of Rockville walked in the same area with a friend. Martinez is starting his junior year in high school. He could, under the curfew proposal, be a violator.

“It’s not right,” Martinez said. “It’s the weekend. It’s supposed to be enjoyed, not under control.”

Leggett, the leading proponent of the curfew, said the aim is to stop trouble before it happens. “I’m going to err on the side of providing protection,” Leggett said. “You don’t want to wait until the problem consumes you. I’m not going to do that.”

Although overall crime and gang incidents in the county are down, Leggett and Police Chief J. Thomas Manger said they worry about increased juvenile arrests, and not just in Silver Spring.

At a recent council meeting, Manger ticked off some summertime incidents: 12:45 a.m., Bethesda, three juveniles arrested trying to break into a car; 3 a.m., a neighborhood four miles west of downtown Silver Spring, two groups of kids flashed gang signs, and one was stabbed; 12:30 a.m., Olney, a juvenile stabbed during a drug deal.

But such late-night crimes are hardly the norm. Last year in the county, youths were arrested in connection with about 323 assaults, only 25 of which happened after proposed curfew hours. Juveniles were arrested in connection with 54 robberies in 2010, nine of those during times the curfew would be in effect.

“Typically curfews aren’t that effective. They target the wrong hours, and they don’t have any teeth,” said John Roman, a senior fellow in the Justice Policy Center at the Urban Institute, which studied Prince George’s County’s curfew in the late 1990s.

Council members Phil Andrews (D-Gaithersburg-Rockville) and Marc Elrich (D-At Large) said they also are concerned about the possibility of racial profiling. And they said a curfew wouldn’t deter the most dangerous teenagers.

Council member Craig Rice (D-Upcounty), who is black, said he’s “90 percent there” in supporting the curfew, even though he said he was once a teenage victim of racial profiling. Rice said that when he was 17, he was pulled over while driving a Volvo and listening to hip-hop.

Still, Rice said he thinks a curfew could be effective.

Proponents also stress that although most teens hang out peacefully, sometimes things can go bad quickly.

On a recent Friday night, Sgt. Mark Miller was on patrol in downtown Silver Spring. By 11:45 p.m., the crowd had thinned enough for him to take a dinner break at a nearby police station, but he only got a few bites down.

One mile north, said the call on his radio, someone fired a gun. Minutes later, he pulled up to a parking lot teeming with teenagers and young adults.

Miller and his colleagues started piecing together what happened: A teenager threw a party and, as word spread through text messages, the crowd swelled to more than 50.

One uninvited guest took a Sony PlayStation III, tucked it in his bag and left. A host followed him into a parking lot, and the thief pulled a gun from his trunk. A shot was fired, but no one was struck. Still, dozens of teenagers continued to hang around within two blocks of the party. It was 12:30 a.m. Miller asked a handful their ages; 16, 17, 18, 19, they said. Miller has concerns about a curfew and worries it could eat up his patrol time. He also wanted the youngest people in the crowd to go home but had no way to force them. “This would be a nice time to have that law,” he said.