The small sedan slowed as it approached the U.S. Border Patrol checkpoint on a deserted section of Interstate 8 east of Yuma. The car contained three middle-age women on their way back to the Valley after a planning retreat in San Diego.

The past three days had been idyllic and productive as the women lounged on the beach, making art and chatting over ideas for the future of their ceramics business.

The self-described hippies had taken marijuana to the beach and were returning with some of it in the car. One of them, Mary (like others quoted in this article, she agreed to talk about her experience only if New Times used a pseudonym) was unapologetic.

"I would never quit. I like my life, you know?" the 56-year-old says later of her pot use. "None of us drink. We're leftover people from the '60s and '70s."

Mary, the oldest of the group, was driving. She didn't sweat the traffic stop as her car rolled up. She'd been through this same movable checkpoint along the stretch of I-8 East before and had never had a problem.

This time, something was different. She noticed that the checkpoint seemed better staffed than usual. One green-shirted agent manned a small, white booth while others milled about near tents, office-trailers, and patrol cars. Another agent walked a dog, which held its snout high as it sniffed along a line of slowing vehicles.

As Mary's sedan neared, the dog tensed as if it had seen a rabbit, straining at its leash and jerking its human handler forward. Mary was told to park her car under a large canopy to the right of the road. An agent walked up to the driver's-side window and asked her if she would consent to a search of the vehicle.

"This was pretty intimidating," she recalls. "They had guns and were wearing fatigues. We're three little ladies from Phoenix who are calm, peaceful people."

The women were asked to step out and stand a few feet away as the dog trounced through the car.

A moment later, one of the agents confronted the group.

"Well, you obviously don't have any illegal immigrants in the car," he said. "My dog signaled for marijuana. Does anyone want to say anything?"

The women said nothing, but the agents soon found about a half-ounce of pot and a small wooden pipe. The women were made to sit in a holding cell in one of the Border Patrol trailers.

"I was, like, 'Come on. I'm a grandma,'" says Mary. But the agents showed no reaction to her plea. Mary took the blame for the pot and paraphernalia because she says it was "critical" that her business partners have no arrest record.

An agent handed Mary, who had never before been busted for anything harsher than a traffic violation, a citation listing two charges: possession of marijuana and possession of drug paraphernalia.

For additional photos from the border check points near Yuma, check out the slide show: Pot Shots

Stories like Mary's used to be rare, compared to what's going on at the Border Patrol's two Yuma Sector checkpoints nowadays.

In the past, small-time drug users were busted occasionally. The Border Patrol has used dogs at its checkpoints for at least two decades, mainly for the purpose of detecting human cargo. But until a few years ago, it employed far fewer than it does now, which meant dogs were not routinely placed at the checkpoints near Yuma. Also, the checkpoints were often closed because fewer agents were available to staff them.

Since late 2005, though, the number of Yuma Sector agents has risen 55 percent — to about 850 agents, up from 550, as of January. Augmenting those agents are hundreds of National Guard soldiers who are part of a 6,000-troop border-protection plan called Operation Jump Start, ordered by President Bush in mid-2006.

The number of K9 dogs also has increased, to more than 30, up from four in 1999. The animals are trained to sniff out hidden human beings, marijuana, cocaine, methamphetamine, heroin, and meth-related drugs such as Ecstasy.

The beefed-up resources and the addition of more than 50 miles of fencing along the border south of the Yuma area have slowed illegal immigration in the sector to a trickle compared with what it was just two years ago.

These days, the checkpoints on eastbound Interstate 8 and northbound Arizona 95 near Yuma (a passageway to the I-10 and I-40 corridors linking Arizona and California) are open 24 hours a day. And with the addition of seven times more K9 dogs, they have become the biggest weed traps in the country.

Strictly in terms of quantity, other checkpoints catch more dope. The Border Patrol is allowed to set up roadblocks as far as 100 miles from any national border, and it operates 33 permanent and numerous other "tactical" or movable checkpoints on the Mexican and Canadian frontiers. In the Southwest, checkpoints are typically found on California's north-south I-5, numerous small highways near Mexico, such as Arizona's Highway 86, and along I-10 between Tucson and El Paso, Texas. The Border Patrol sometimes puts up movable checkpoints on I-10 between Phoenix and Los Angeles, but it's rare to encounter one.

Drug-sniffing dogs at some of the checkpoints, especially the ones south of Tucson and through Texas, find literally tons of marijuana being smuggled from Mexico.

But the Border Patrol and other law enforcement officials in the Southwest report that no checkpoints in the United States bust as many small-time marijuana users as the ones near Yuma, on I-8 and Arizona 95.

The past three years have seen an explosion of such cases. In just 11 months last year, the two checkpoints nabbed more than 1,200 people for possession of marijuana — and usually for smaller amounts than what Mary carried.

The majority of the busts occurred at the checkpoint along eastbound I-8, the freeway that carries vacationers between Arizona and San Diego.

Consequences are toughest for people caught with hard drugs. Possession of such drugs as meth, cocaine, or heroin will result in a long drive to the county jail in Yuma. But even for personal amounts of marijuana, citations are issued that can result in fines and big hassles.

The I-8 checkpoint garnered national attention in January after rapper Lil Wayne was arrested there. He was charged with carrying marijuana, cocaine, Ecstasy, and a handgun. He pleaded not guilty last month.

Few would argue that big dope smugglers or those carrying an arsenal of hard drugs shouldn't feel the pinch of the law. If it weren't for the trained dogs, smugglers could run thousands of pounds of drugs through the Yuma Sector checkpoints.

But the vast majority of people getting busted at checkpoints in Arizona near Yuma aren't smugglers or illegal immigrants. They aren't even big-shot partiers like Lil Wayne. They're just average people who happen to be carrying a smidgen of marijuana in their vehicles.

They might never be caught if it weren't for an exception granted the Border Patrol to set up roadblocks with trained dogs. All the Border Patrol checkpoints, not just the ones near Yuma, take advantage of special powers that experts say contradict normal constitutional search-and-seizure rules.

So many marijuana users have been caught that, last year, Yuma officials had to streamline the legal process. In a program unique to the Yuma Sector, Border Patrol agents were given the authority to write citations in low-quantity marijuana cases as though they were deputies working for the Yuma County Sheriff's Office.

The program even was anointed with a catchy federal handle: Operation Citation.

The deputizing of the federal agents means it's easier than ever to get busted. And the program reflects how busting minor pot users is what the agents working at the checkpoints — whose primary mission is supposed to be stopping illegal human trafficking — spend much of their time doing.

A review of 1,052 of the citations issued last year showed that more than 40 percent were issued to Arizonans, presumably on their way back from California. Of those, Phoenix and Tucson residents made up the majority. The rest were split among Californians, 44 percent, and people from other states. A handful of those cited listed hometowns in other countries, including Mexico, Spain, England, and Austria.

Most were cited for possessing just a few grams of marijuana, or a pipe containing marijuana residue. (A gram is about the weight of a large paper clip).

If there's more than one person in the vehicle and no one admits ownership of the marijuana, Border Patrol policy dictates that the citation goes to the driver.

It's not just the number of dogs that makes the Yuma checkpoints so different. Border Patrol checkpoints just a few miles away near El Centro, California, including a new one on westbound I-8, also use dogs. But marijuana laws are far more lax in California, resulting in far fewer citations and much-less-serious legal problems.

In the unlikely event that you do get busted on your way to San Diego for a small amount of marijuana at the California-side I-8 checkpoint west of the state line, you will be hit with nothing more than a $100 fine. In California, possession of an ounce or less of pot is not even prosecuted as a misdemeanor, it's a base-level "infraction."

But you'd better not risk bringing even a tiny amount of pot back from the beach — because nothing demonstrates how differently marijuana possession is viewed officially by California compared to Arizona than the checkpoint busts this side of Yuma.

Arizona has the stiffest marijuana laws in the country. Possession of any amount or of any kind of drug paraphernalia (even a small pipe) is technically a felony.

Technically, because charges against small-time users are knocked down to misdemeanors in Yuma County and in other Arizona counties, including Maricopa. Leniency is one reason — marijuana isn't considered as dangerous as other drugs. But it's also true that, if prosecuted as felonies, the sheer number of marijuana cases would overwhelm local court systems.

Still, a misdemeanor conviction for pot means that you must pay hundreds of dollars in fines in Arizona. And, it's not uncommon for defendants to fork over thousands of dollars in attorney fees trying to avoid a conviction — which, for some, means loss of a job or disqualification for federal financial aid.

The Border Patrol is unapologetic about its right turn toward busting hordes of minor drug offenders at the Yuma-area checkpoints. In fact, Jeremy Schappell, spokesman for the Yuma Sector, brags that the agency practices zero tolerance when it comes to any amount of illegal substances or paraphernalia.

"If we get just a pipe, they are getting written up," Schappell says. "If it's a seed, they are getting written up."

Using drug-sniffing dogs at checkpoints to catch small-time marijuana users probably seems like a smart idea to Americans who view drug use as morally unacceptable.

However, keeping in mind the Fourth Amendment's prohibition against unreasonable searches and seizures, judges have traditionally taken a dim view of such "suspicion-less" stops and searches of vehicles.

After first taking office in 1993, Sheriff Joe Arpaio, a former DEA agent, proposed staking out main roads in and out of Maricopa County with checkpoints. Then-County Attorney Rick Romley put the kibosh on Arpaio's idea, saying it was unconstitutional.

In 2000, the U.S. Supreme Court struck down another drug checkpoint proposal in Indianapolis vs. Edmond. In the landmark case, Indianapolis police set up roadblocks staffed by dogs and their handlers, ultimately busting about 50 people with drugs.

The Supreme Court had, in the past, found two major exceptions to its general disapproval of police checkpoints. In 1990's Michigan Dept. of State Police vs. Sitz, the High Court allowed DUI checkpoints. And in 1976's United States vs. Martinez-Fuerte, it gave the Border Patrol the right to set up checkpoints that seek to uncover illegal immigrants — with the secondary purpose of finding drugs.

"We have never approved a checkpoint program whose primary purpose was to detect evidence of ordinary criminal wrongdoing," the Supreme Court majority wrote in the Indiana case. "The [Indianapolis] checkpoints violate the Fourth Amendment."

The notion of a checkpoint where police can pull over every single vehicle and search it chills many Americans. Justice Clarence Thomas, no beacon of liberal thought, made that clear in his dissenting opinion in the 2000 case. Though Thomas felt compelled to side with the Indianapolis police because of court precedents, he challenged the basis of the precedents strongly.

"I am not convinced that Sitz and Martinez-Fuerte were correctly decided," Thomas wrote. "Indeed, I rather doubt that the framers of the Fourth Amendment would have considered 'reasonable' a program of indiscriminate stops of individuals not suspected of wrongdoing."

The new agreement with Yuma County blurs the distinction between drug and immigration checkpoints.

The Yuma County Sheriff's Office, like all other law enforcement agencies in the country, cannot legally operate a K9 checkpoint. But in Yuma County, Border Patrol agents are deputized to write local-jurisdiction citations — an end run around long-standing constitutional protections against stopping motorists without probable cause.

The Border Patrol takes pains to explain that it's running immigration checkpoints, with the secondary mission of detecting illegal drugs, just as the Supreme Court's legal interpretation allows.

Graham Boyd, director of the American Civil Liberties Union's Drug Law Reform Project in Santa Cruz, California, says the procedures at the Yuma checkpoints are a good example of how increased police powers for one purpose often end up being used for another. The supposed need for an immigration checkpoint is "thin justification" for busting every drug user passing through, he insists.

"Even if somebody has no sympathy for a marijuana user," Boyd says, "you should still be concerned that the U.S. government is saying the border is an area where the U.S. Constitution is suspended."

On a recent winter day at the I-8 East checkpoint, two skinny young Hispanic women are led away in handcuffs. A Department of Public Safety Officer helps them into his patrol car for a trip to the Yuma County Jail.

A checkpoint dog found meth in the women's car.

The dogs working the checkpoint that day were Belgian Malinoises, though the agency also uses German shepherds, Labradors, and other breeds. They're kept fit and trim — so lean, in fact, that motorists often urge the agents to feed them more. It takes about six weeks to train the dogs to sniff out drugs and people, then another six weeks to train their handlers, says Wes Burch, the Yuma Sector's K9 coordinator.

To the animals, the work is a fun game of hide and seek. Sometimes, they can smell drugs from dozens of feet away as they walk along the queue of slowly rolling vehicles. A dog's body posture changes if it catches a whiff of drugs, becoming more rigid and focused. Its breathing quickens. After the vehicle is emptied of visible occupants, the dog is nearly infallible at finding drugs or people hidden inside. If drugs don't turn up, it doesn't mean they weren't there earlier. A Border Patrol K9's sense of smell is so acute, agents say, that it can tell if someone smoked marijuana in or near a vehicle days before the checkpoint stop.

When they find drugs, the dogs are rewarded with a small burlap toy for a few moments. The animals seem to love their job, eagerly sniffing within inches of vehicles, putting their paws on truck bumpers, and scanning the air with their snouts.

These days, there are enough trained canines to allow for rotating shifts. Still, the job is fairly intense for the dogs. They can focus on their work for only 15 or 20 minutes at a time before needing a break; their sense of smell is diminished when they become overheated. Despite the boost in dog teams that has led to increased drug busts, it's possible to pass through the checkpoints without ever seeing a dog.

At least three dogs are working on the day New Times visits the I-8 East checkpoint, but the animals rest more than half of the time. Even when the dogs are ready, sometimes the line of vehicles becomes too long and has to be "flushed," as the agents put it. All but the most suspicious autos are waved through quickly. Otherwise, commerce and the free flow of traffic on the highway would be disrupted, agents say.

One K9 handler walks far down the shoulder of I-8, using his dog to sniff out small bags of drugs and paraphernalia often discarded by approaching drivers or passengers. He finds nothing on this day, but it's common to find such contraband near the checkpoint, says Schappell, the federal agency's Yuma spokesman.

Schappell wonders why a Border Patrol sign announcing the checkpoint about a mile up the road doesn't warn all drug users to dump their stashes. But he fails to realize that most people have no idea their vehicles are about to be sniffed by a dog, with major consequences if the animal smells anything alarming.

The I-8 East checkpoint does have a sign declaring, "Working Dogs Ahead." But it's next to the checkpoint booth and the dogs, making it useless as a warning.

A lean, gray Belgian Malinois suddenly appears happier, its attention focused on a gold Chrysler 300. It tugs firmly at its short, leather leash, and its handler motions to another agent, who asks the 20-something driver to pull over beneath a shade tent. The young man sits on a folding chair for a few minutes, looking nervous. As the Malinois bounces through his car, he leans forward with his head in his hands.

But the dog finds nothing, and driver is released.

As far as the agents are concerned, a K9 is never wrong: The man must have had drugs in or around his car recently that left enough lingering molecules to alert the dog.

To Yuma County, the Border Patrol's dogs look more like geese — as in the ones laying golden eggs.

They've brought in hundreds of thousands of dollars in the past few years. Until a change was made last fall, fines ranged between $750 and $1,400 for the small-time marijuana violators picked up at the checkpoints. Now, fines usually run $400 — but that still works out to be a lot of money considering there have been more than a thousand cases a year.

And considering that federal agents and their dogs do most of the work.

Yuma County officials insist it's not about the money. They say it's a black-and-white issue. Marijuana is illegal.

"It's the law, and we like enforcing the law," says Roger Nelson, chief deputy Yuma County attorney for criminal matters. "We're not going to apologize for it, and we don't think there's anything wrong with having drug-sniffing dogs at an immigration checkpoint."

Though the Border Patrol is a federal agency that's using its resources to do the work of Yuma County authorities, Schappell says it "can't turn a blind eye" to the casual users picked up because of the extra dogs.

The issue of whether the federal Border Patrol officers near Yuma should be busting small-time drug offenders is a subject made raw over the recent death of a comrade.

In mid-January, Agent Luis Aguilar was run over in the sand dunes west of Yuma by a Mexican national driving a Hummer loaded with drugs.

"My opinion is that the grandma coming through with the ounce of marijuana — how she got the marijuana is from the Hummer that ran over Luis Aguilar," Schappell says.

The Yuma Sector's spokesman finds it ironic that media focused far more on the January 22 arrest of entertainer Lil Wayne, which happened two days before a memorial service was held for Aguilar. Media calls poured in from all over the world about the rapper, but reporters weren't very interested in the dead agent.

Lil Wayne, whose real name is Dwayne Michael Carter Jr., was riding in an RV with 11 friends when a dog targeted his vehicle at the I-8 East checkpoint. A subsequent search turned up about a quarter-pound of pot, an ounce of cocaine, 41 grams of Ecstasy, and a handgun.

Interest in what happened to Lil Wayne has been running so high that the Yuma Superior Court plans to air live coverage of his upcoming trial (no date for which has been announced) on its Web site.

Another big catch apparently flew under the media's radar: Officials say that in 2006, a dog at the I-8 East checkpoint hit on the tour bus of the Crosby, Stills and Nash band, resulting in an arrest for hashish. It wasn't one of the famous musicians who got nabbed, but a member of their entourage.

Interestingly (because it would make sense to rationalize the huge number of minor drug arrests as a means of keeping impaired motorists off the highway), none of the marijuana users cited at the Yuma Sector checkpoints was busted for driving under the influence.

The Border Patrol's heightened checkpoint activity played a big role in boosting the number of misdemeanor cases handled by the Yuma County Attorney's office from 980 in 2000 to more than 1,500 by 2005.

Then it really got busy. Nelson says his office prosecuted more than 2,500 misdemeanors last year. And that's despite the fact that county attorneys routinely dismiss as many as 20 percent of the marijuana cases as too legally tenuous to bother with.

Not surprisingly, Nelson says it was his office that recommended the partnership between the Border Patrol and the Yuma County Sheriff's Office, which led to the current arrangement of having the federal agents write Arizona tickets.

Before Operation Citation, the Border Patrol agents would make a seizure, then forward the motorist's name to the county attorney's office. Nelson says prosecutors would be forced to send a registered letter to each defendant at the cost of $5 or $6 each. And sheriff's deputies routinely had to schlep out to the Border Patrol stations to pick up the contraband for evidence, then write a slew of citations.

Now, county officers are no longer faced with the dilemma of either doing all that work or ignoring the fine-producing cases.

As for the people busted at the checkpoints who talked to New Times, they are angry that an immigration-enforcement agency caught them in its lair. They believe it's only natural that they had no idea they would be detained, because they weren't carrying a secret cargo of illegal aliens.

"I don't mean to be a conspiracy theory person, but you have to wonder if we are heading for the same things the Germans went through," says Mary, the pot-smoking grandmother. "It's only a matter of time before we see [checkpoints] on I-17 and every other major highway."

"It definitely didn't feel American," a member of a small Texas rock band says about the I-8 East checkpoint, after receiving a citation in June. "Our civil liberties are kind of slowly corroding away."

Normally, a police officer is allowed to pull over a motorist only if a traffic violation (anything from erratic driving to a busted tail light) is observed. Then, the officer has probable cause to, say, shine a flashlight into the car to look for illicit drugs.

Though there was no such probable cause in the Yuma County pot cases, the Border Patrol is exempted from that requirement by the Supreme Court, as noted earlier in this story.

The busted motorists whom New Times interviewed were particularly chagrined that a dog wound up leading officers to the pot they had stashed in their luggage.

"We were stupefied by the whole thing," says a 39-year-old Colorado mother of two teenagers charged with possessing about four grams of marijuana. She'd been on a road trip with a friend from Texas to San Diego, and they'd stopped in Tucson to visit a mutual friend, who gave them the pot. A highway accident temporarily closed I-8 East, diverting traffic north from Yuma onto Highway 95 — right into the northbound checkpoint where a Border Patrol dog was waiting for them.

"We thought we were going to be thrown in prison or jail or something," she says. "It was one of the scariest things I've ever been through."

She later paid $1,600 for an attorney (to avoid having to fly back to Yuma for a court date) and a $400 fine.

In cases like that of the Colorado woman, leniency figured into the equation, according to Yuma County prosecutors.

Nelson, the chief deputy county attorney for criminal matters, says his office prosecutes minor marijuana cases as misdemeanors to provide "the lenience that we believe these crimes deserve."

Truth is, Yuma County's courts would be swamped if each small-time pot case were handled as the felony that state law declares it, says Lil Wayne's Yuma attorney, James Tilson. The county, like most others in the state these days, is under a major budget crunch.

So, there's a practical reason for dealing with people caught with small amounts of marijuana quickly and efficiently. Doing it otherwise, simply doesn't pencil out.

More arrestees would take felony cases to trial. Even with plea agreements, such cases take a lot more time, money, and effort to prosecute.

On both the financial and human level, "increasing the amount of work you have doesn't make sense if it's not a serious crime," Tilson says.

Unfortunately for those caught on the Arizona side of the state line, a misdemeanor still packs a punch. Besides a fine, it also requires defendants or their lawyers to appear in court, which can get expensive.

Mary, the Phoenix grandma, negotiated a deal in which her misdemeanor charge was dropped in lieu of a $1,200 drug-treatment class. She paid a lawyer $3,500 to help make the deal.

The Texas musician paid a lawyer $3,500 just to see a $738 fine dropped to $400.

Under the current system, an innocent person could easily end up with a ticket just because a pot user left a surprise in the car.

That's what happened to "Joe," a 48-year-old Peoria man who drove his wife's car through the checkpoint on his way back from a job in Yuma. Joe's not a pot smoker and says he fully supports the Border Patrol's mission.

"My daughter, who's in her 20s, forgot to take her goodies out" of the car, Joe says. After a dog gave an alert, agents found two used pot pipes in the trunk.

Rather than place the blame on his daughter, he paid $1,600 in fines, and was embarrassed recently when the arrest showed up in a background check while he was trying to rent a house. He was allowed to move in, but lamented of his new rap sheet: "It just sucks. Period."

The worst part, Joe says, is that he could be fired if his boss ever found out about the conviction.

Ryan Childers, a criminal defense attorney who worked as a prosecutor for Imperial County, California, from 2004 to 2006, was surprised to hear how many checkpoint-related drug cases Yuma County handles.

"What a waste of resources!" the El Centro lawyer says.

In California, Childers explains, possession of an ounce or less of marijuana rates only a $100 fine and is considered a minor infraction rather than a misdemeanor. And forget the rhetoric heard in Arizona that violators would be prosecuted even "if it's a seed." This state's more liberal neighbor requires a "smokable amount" to prosecute the infraction, Childers says.

The law against marijuana paraphernalia in California is so lax that Border Patrol agents in the state who find a pipe or a bong in a checkpoint search can't do anything other than confiscate it, Childers says.

There's no checkpoint along the westbound lanes of I-8 in Arizona, but three months ago, the Border Patrol opened a checkpoint on westbound I-8 just east of El Centro. The agency's El Centro Sector also operates permanent checkpoints on California highways 86 and 111.

Minuscule amounts of marijuana are mostly seen as a waste of time for law enforcement, says Lieutenant George Moreno of the Imperial County Sheriff's Office.

A sheriff's deputy or a California Highway Patrol officer is obliged to drive out to the El Centro-area checkpoint if a case is to be made. Moreno says California law disallows detentions of more than 30 minutes for infractions. So if the amount of pot is just a few grams and no deputy is near the checkpoint, the sheriff's office doesn't send anybody out.

"The Border Patrol knows that we don't have the staffing levels, so they [usually] just let the person go and they destroy the evidence," he says.

And because California's medical-marijuana law is liberal, if such marijuana users show the correct paperwork to the Border Patrol after getting stopped, their pot is seized and they're sent on their way, Moreno says.

In the Yuma Sector, low-level busts of people with marijuana are staving off boredom for Border Patrol agents.

Spokesman Schappell talks almost wistfully of the days when the sector was hopping with illegal immigrants. Now, agents don't spend much time chasing down border crossers and hauling in big loads of drugs, he admits.

On a sunny February day, Schappell cruises a sandy road on the northern side of the imposing security fence that runs from San Luis to just past the distant Tinajas Altas Mountains on the horizon. Not a footprint can be seen for miles in the soft earth.

"Anybody who says a fence doesn't work, I say, 'Come to Yuma,'" Schappell says.

The number of Border Patrol agents nationally stands at more than 15,000 and is expected to grow to 18,000 by the end of the year. The push toward greater enforcement against illegal immigrants is gaining momentum, and agents from Texas to California insist that checkpoints are a crucial part of the system.

Checkpoints running north from Tucson and ports of entry in New Mexico and Texas caught the bulk of the nearly 2 million pounds of marijuana, seven tons of cocaine, and sizable loads of other drugs seized by the Border Patrol last year.

In the Yuma Sector, though, the agency's mission has changed with time. Now, it's the small-time drug offender feeling the most heat, and the illegal immigrants and smugglers — who are far more aware of the checkpoints than the average American citizen — are going elsewhere.

The Border Patrol attributes this to the addition of the 300 new Yuma Sector agents in three years and to the new fence along the non-mountainous parts of the sector's 125-mile southern border.

The drop in apprehensions has been the Border Patrol's biggest success story. In 2006, Yuma Sector agents caught 118,000 people trying to gain entry into the United States from Mexico. But last year, only 39,000 people were apprehended in the sector.

Rock-throwing by Mexicans south of the border has become more common — agents believe it's a sign of frustration with the new situation.

Still, most Yuma-area Border Patrol agents are now watching over a relatively quiet border.

Most of the action takes place at the checkpoints, where agents busy themselves busting the likes of pot-smoking grandmas and musicians.

Many of the busted marijuana users interviewed by New Times wondered whether Border Patrol agents had too much time on their hands, considering that agents expend so much effort to catch people carrying mostly minuscule amounts of pot. Others wondered whether Operation Citation was just a clever way to pour money into the Yuma County coffers.

"It's like a toll booth," says a New Mexico man busted for marijuana possession last year at the I-8 checkpoint with his two sons, in their 20s.

Whatever the frustrations of motorists who like to imbibe in a little pot, drug-sniffing dogs at the Yuma-area checkpoints are here to stay.

Lloyd Easterling, an assistant chief at the Border Patrol's Washington headquarters, says the agency is proud of the Yuma Sector's ongoing effort to nail drug violators.

"Whether it's small-time offenders or much-larger-time smugglers, those drugs are still coming in and out of the neighborhoods," Easterling says. "At some point, the likelihood is that they came across the border."

In Arizona, a misdemeanor conviction for pot means hundreds of dollars in fines. It's not uncommon for defendants to fork over thousands of dollars in attorney fees trying to keep from getting a drug record.

Nothing shows how differently small-time pot possession is viewed in California compared to Arizona than the checkpoint busts this side of the state line. Such Border Patrol busts are rarely pursued by California authorities. When they are, only a small fine is levied.

Of 1,052 people cited for small amounts of marijuana last year at the checkpoints near Yuma, 40 percent were Arizonans, presumably on their way back from California. Of these, most were from the Valley.