The Netherlands is embarking on a crusade against its multi-billion-euro marijuana industry, with significant implications both for its economy and its famously liberal approach to life. Along with tighter control of legalized prostitution and a swing to the right in attitudes toward immigration and Islam in recent years, the clampdown is seen as further evidence of an erosion of tolerance in a country known for its liberal social policies. The push to clamp down on soft drugs has come mainly from the Christian Democrats, the junior partner in the minority government and one of the larger parties in a fragmented political landscape. "There's clearly a shift in the moral debate. It's all about the culture of control," said Dirk Korf, professor of criminology at the University of Amsterdam. Instantly recognizable from the sickly sweet, burned-leaf smell that wafts out onto the street, the Netherlands' world-renowned "coffee shops" are almost as common as supermarkets in big cities such as Amsterdam and Rotterdam and in certain border towns. Like trained sommeliers, the staff or "bud tenders" are experts on the flavors and after-effects of whatever is on the menu -- white widow, vanilla kush, or hazers like amnesia "known for its extreme, almost paranoid psychedelic high, with an unforgettable strong fruity taste and smell." Counter staff do a brisk trade in plastic sachets of loose grass, ready-rolled joints and chunks of hashish for those who want take-away. The Netherlands tolerates the sale of up to 5 grams per person per day of marijuana and hashish in the controlled environment of the coffee shops. It also tolerates the home cultivation of marijuana plants, within a limit of five plants per person, but any cultivation larger than that is illegal. Strong demand has spawned secret cannabis plantations that provide a so-called back-door supply to the coffee shops and are a headache for Dutch authorities who have to find and raid them. DRUGS TOURISTS On a typical Saturday evening, the coffee shops in central Amsterdam are packed with smokers. The clientele is middle class, the voices mostly foreign -- Italian, Spanish, French, German, English. Concerned about this influx of soft-drugs tourists, not to mention what it sees as the associated crime, nuisance and health risks, the Christian Democrat Party wants to see the country's 700 or so coffee shops shut down, but for the moment is settling for introducing restrictions on their activities. A measure expected to be passed in parliament by the end of this year will have coffee shops operate as members-only clubs, meaning that only local residents will be eligible to register for "weed passes," effectively barring foreigners from buying soft drugs. Already, some cities have introduced tighter restrictions, limiting the coffee shops' proximity to schools or relocating them to the outskirts. On October 1, coffee shops in the southeastern city of Maastricht banned all foreigners except for neighboring Germans and Belgians, as a first step toward introduction of weed passes. Crime expert Korf says there is little justification for the clampdown, with scant evidence that the Dutch public supports the change. "No serious polls have been conducted, we don't know if opinions about coffee shops have even changed," said Korf. "Before coffee shops we had street dealing, they were selling marijuana in the street and ripping off tourists. The whole drug problem is nothing compared to (what we had in) the 1980s, 1990s -- we don't have a heroin problem." The Trimbos Institute, which studies addiction and mental health, said 5 percent of Netherlands citizens smoked weed or hashish in the past year, against an EU average of 7 percent. GLOBAL CONFUSION Policymakers around the world are seeking fresh ideas on how to combat drug abuse, opening up a debate on policies on soft drugs. In June, a high-profile group of global leaders declared the "war on drugs" a failure and urged governments to consider decriminalizing drugs in order to cut consumption and weaken the power of organized crime. The Global Commission on Drug Policy -- which includes former Brazilian President Fernando Henrique Cardoso, former U.N. Secretary-General Kofi Annan, former U.S. Federal Reserve Chairman Paul Volcker and British billionaire Richard Branson -- said a decades-long strategy of outlawing drugs and jailing users while battling drug cartels had not worked. It recommended that governments experiment with the legal regulation of drugs, especially cannabis, citing the successes in countries such as the Netherlands, Portugal and Switzerland, where drug consumption had been reduced. Portugal, for instance, has gone much further than the Netherlands by decriminalizing all drugs, replacing jail time with counseling and treatment. The Christian Democrats disagree and say the Dutch policy has had a negative effect on public health and crime. "In other countries there is no tolerance. The Dutch coffee shops attract a lot of foreign drug tourists, especially in the border region, causing much nuisance," according to a statement published on the Christian Democrat Party website. The centrist party has cast doubt on the rationale for allowing coffee shops, which was to separate the soft and hard drugs markets, and said that people who smoke cannabis often turned to other drugs. It also argues the active substance in cannabis is much stronger than twenty years ago, putting it on a par with harder drugs -- a reflection of years of cultivation of new varieties by growers. A Dutch commission earlier this year found that hashish and marijuana on sale in the Netherlands contain about 18 percent of THC, the main psychoactive substance, and said a level above 15 percent put the drugs on a par with heroin or cocaine. Maxime Verhagen, a Christian Democrat who is deputy prime minister, said on October 7 the government would ban the sale of cannabis whose concentration of THC exceeds 15 percent. The Christian Democrats also want tougher regulations on the so-called cannabis plantations. In addition to illegally supplying the coffee shops, "much of the illegally cultivated cannabis in the Netherlands is exported abroad. There is an extensive network illegally created in the grip of organized crime," the party said in its statement. Dutch authorities already devote considerable resources to tracking down these large-scale plantations. The police work with the local electricity company to detect unusual consumption patterns, for example round-the-clock usage in sheds and attics, and have used tiny sniffer-helicopters which can detect the smell of pot plants wafting from ventilation shafts and chimneys, according to media reports. Rotterdam city council recently distributed "scratch and sniff cards" to households, hoping that concerned citizens would tip off the police if they recognized the smell of illegal cannabis plantations in the neighborhood. PUSHBACK AT HOME There is plenty of opposition to the crackdown. Dutch smokers do not welcome the idea of having to register for weed passes. "Many of my customers are locals, artists, writers, doctors, lawyers, professionals. They don't want their name on a register -- they don't know who could see it or use it. So they may go to other sources on the street," said Paula Baten, manager of the Siberie coffee shop in central Amsterdam. "This government is more Christian, more right-wing. They don't want drugs but they forget about the effects of alcohol." Already, there's talk of how foreigners can circumvent the new rules, for example by asking Dutch citizens to buy soft drugs on their behalf to take away, and concern that dealing in soft drugs will go onto the street. Some politicians oppose the proposals. Eberhard van der Laan, the mayor of Amsterdam, says restricting the activities of coffee shops would lead to greater health risks, nuisance and drug dealing on the streets. As mayor, he could simply choose not to enforce the weed pass regulations. "At the moment the mayor is in conference with the minister to convince him that the measures regarding coffee shops will be counterproductive for Amsterdam," the mayor's office said in a statement to Reuters. Others cite the likely economic impact. The Netherlands, like other European countries, has had to introduce austerity measures and cut spending in the wake of the credit crisis, when it pumped 40 billion euros into rescuing financial institutions. Tax revenue from the coffee shops is estimated at about 400 million euros a year. Studies by the finance ministry and academics estimated that if the Netherlands legalized the "back-door" supply, bringing it "above board," it could collect as much as an additional 400-850 million euros a year, including savings on the cost of law enforcement. Then there's the tourist revenue. In Maastricht, which gets a lot of day tourists because it is so close to the German and Belgian borders, a study commissioned by an association of coffee shop owners calculated that visitors to the city's coffee shops spent about 119 million euros a year, mostly on shopping and eating out. A study by Professor Korf of the University of Amsterdam found that tourists who visited coffee shops in central Amsterdam had similar spending habits to other tourists, and were just as likely to spend 200 euros or more on a hotel room, or splash out at smart restaurants or nightclubs. The Bulldog and Barney's -- the big names in the industry -- run coffee shop chains, and many coffee shop owners also make money from lodgings and related businesses. Hundreds of tourists attend the annual cannabis cup award for the best new strains, and the local edition of Time Out runs monthly weed reviews. Jackie Woerlee, who runs customized cannabis tours, said that among her recent tour guests were members of one of the Middle East royal families who rented a luxury apartment for several weeks and spent several thousand euros shopping at luxury stores. "Customers might easily spend 100 euros in a coffee shop, but it's not just that, it's the hotels, the eating out, renting apartments," Woerlee said. "These people spend."