Standing in the checkout line in Aisle 2 at a brightly lit Safeway on Rhode Island Avenue NE, an 18-year-old woman in a black top and bluejeans is waiting to buy alcohol.

Minutes before, she'd been rebuffed by a mom-and-pop convenience store a couple of blocks away. The cashier said she was too young. But this time is different.

The young woman plops down a four-pack of Bartles & Jaymes wine coolers on the counter and hands the 27-year-old clerk a $20 bill. The clerk asks for no identification and simply returns the change.

The teenager briskly exits the store, with an undercover police officer and alcoholic beverage investigator following close behind. Minutes later, the store is busted.

"I was like, 'Oh, no, why did she sell?' " the teenager said outside the store. "She should know better."

The teenager is part of an undercover operation involving the D.C. police and the D.C. Alcoholic Beverage Regulation Administration (ABRA), the city agency that is aggressively clamping down on businesses that peddle liquor to minors.

Launched in July 2003, the program has targeted more than 680 bars and liquor, drug and grocery stores in the District and cited 166 of them for selling to minors -- all volunteers from the National Capital Coalition to Prevent Underage Drinking.

"I think it's extremely effective," said Maria M. Delaney, director of ABRA. But she makes a distinction between effective and successful. "To me, a successful program is to have merchants not selling to kids at all."

Delaney said inroads have been made. About 24 percent of all stores visited have sold alcohol to minors since the program began; in January, that figure was 45 percent. Delaney attributes the drop to the undercover crackdown and an educational program for merchants.

At the Safeway last Thursday, as is typical, a D.C. police officer, an ABRA investigator and Delaney returned to the store minutes after the purchase. They summoned the store's alcoholic beverage supervisor and the cashier who sold the liquor. The store employees both later declined to be interviewed.

Craig Muckle, a Safeway spokesman, said, "We're very disappointed that we did not pass the sting operation. We have a very diligent program to get everyone to comply. We understand selling alcoholic beverages is a responsibility. We take it very seriously."

The police officer wrote a citation for a misdemeanor court appearance for the cashier, who at first seemed stunned. The ABRA investigator filled out paperwork for administrative action against the store.

The administrative action involves a "notification" that the store has sold liquor to a minor and is followed up by a letter. The letter typically gives first-time offenders the opportunity to settle for a $1,000 fine. For subsequent violations, the establishment must appear at a hearing before the Alcoholic Beverage Control Board, which can level fines ranging from $1,000 to $6,000. The ABC board's decisions can be appealed to D.C. Superior Court. So far, no business has appealed the ABC rulings, according to Delaney.

If an establishment has four violations in a four-year period, its liquor license is automatically revoked. To add to the penalties, police in February started issuing criminal citations at the same time that ABRA took action. The misdemeanor citations can result in criminal fines of up to $1,000 and one year in jail, though no one has served any time, police say.

Normally, two teams go out most weeks. Each team is made up of one or two teenagers, two to four D.C. police officers and one or two ABRA investigators.

Each time, a police officer and an ABRA investigator enter the store shortly before one or two teenagers go inside. If there's no sale, they move on, no questions asked. If they get a sale, the police and ABRA investigator return immediately and write up the violation.

"I was surprised at how many people would look at my ID and still sell it to me," said Felicia Donelson, 20, who used to make buys but now works for ABRA as a supervisor of the undercover teenagers. She was outside the Safeway during last week's compliance check.

Under the program, all types of businesses have been busted: upscale supermarkets and restaurants and hole-in-the-wall mom-and-pop stores.

In some instances, the teams make return appearances to the establishments, particularly in areas designated as "hot spots" because of high crime rates. The city is attempting to crack down on many forms of illegal activity in those areas.

But some in more trendy neighborhoods have also gotten repeat visits. For instance, Coppi's Pizza on U Street NW refused to sell to an undercover 16-year-old on Jan. 31 but sold to 19- and 18-year-olds on April 16, according to ABRA records.

Carlos Amaya, manager of Coppi's, said the program is fair, but added that he'd thought the teenagers who bought the liquor looked older. He said they also came at a busy time. Still, he said, the waitresses should have asked for identification.

"The law is the law. The effect is a good effect," he said. "Now it's 100 percent ID check, no matter what."

D&B Deli Carryout on Georgia Avenue NW turned away undercover teenagers twice this year, but made one sale on March 6, according to ABRA. Eunice Kim, the cashier at D&B Deli who was on duty when a 14-year-old undercover buyer walked in that Saturday night, said, "At some point it was unfair. The girl who came in to buy beer looked like she was 25."

Kim, whose father owns the business, acknowledged that it was her fault for not asking for identification. But she said she thought the program should use people who look younger.

The teenagers in the program said they have strong convictions about alcohol sales to minors. Selling alcohol is a "very powerful thing in the United States of America," said Donelson, a pre-law student. "Therefore, if you take responsibility to sell this beverage, you also take the responsibility to uphold the law."

Delaney says the program tries to minimize deception.

"The minor cannot wear a lot of makeup, a lot of jewelry to make them look older," she said. The program no longer uses undercover workers once they have turned 20, although in the early days, some buys were made by 20-year-olds.

"They have been instructed that they cannot lie about their age, and they must show proper identification if asked -- if they have it," she said. Some youths are too young to have a driver's license or other official IDs. "They must dress the way youths dress today. We wouldn't dress them up in an evening gown or cocktail dress."

Lynne Breaux, executive director of the Restaurant Association Metropolitan Washington, gives the program high marks.

"It is my understanding it is a good program and it is being handled very properly by ABRA," she said. "There were times in the past that some of the underage participants in this program were surprisingly old in appearance. Now the people participating in the program are extremely youthful in appearance. The subterfuge has certainly lessened.

"I think no restaurant wants to break the law," she added.

A 14-year-old volunteer from Duke Ellington High School, who spoke only on the condition that her name not be used, said she gets angry when stores sell to her.

She said a clerk in Northeast Washington slipped a can of beer into a bag for her, then asked for ID. She told him she didn't have it.

Then he asked how old she was. "I said only 13. And he said, 'Are you sure you're only 13?' He was saying 'Are you sure' as if I had said something else, he was going to sell to me.

"A big problem in my community is alcoholism," she said. "Most people who are alcoholics started drinking when they were younger. I just wanted to go out and do my share and make sure kids around my age or even older do not buy alcohol."

She said she's impressed by stores that don't sell.

One of those was a liquor store in Congress Heights in Southeast Washington. She recalled trying to buy a 22-ounce can of malt liquor. The cashier looked at her and said: " 'Are you crazy? Want me to call the police on you?' I had to hurry up and get out of the store because I thought she was really going to call the police.

"At the time I was kind of embarrassed. Everybody was looking at me. But afterwards, I felt kind of proud about that store in our community. I believe it was black-owned. I felt kind of proud that they would take responsibility and make a difference in their community."

What's most surprising to some of the undercover teenagers is that some clerks sell them liquor after looking at their identification.

One 18-year-old volunteer said she recently bought a six-pack of spiked lemonade at a drugstore in upper Northwest Washington.

"I brought it to the counter and the woman looked at me and said, 'Can I see your ID? You look like a baby.' She looked at me. She looked at my ID, and she said, 'I just had to check because someone keeps getting our liquor license taken away, and I didn't want to take any chances.' And she sold to me. Then the officer went in and she wouldn't take the citation, and they arrested her."

After the clerk came out of the store, the volunteer said, she looked at the teenager and said, " 'I didn't sell to anybody.' Then she changed it and said, 'Oh, no, you sent her in there with a fake ID.' Then she said, 'Oh, you're going to arrest me because I made a mistake?' "

A city alcohol investigator heads into a Northeast Safeway store after an undercover buyer, right, purchased wine coolers there. At right, Felicia Donelson, a former buyer, says, "I was surprised at how many people would look at my ID and still sell it to me."