A minor issue at the Minneapolis-St. Paul International Airport (MSP) has potentially major implications for the future of Islam in America. Starting about a decade ago, some Islamic taxi drivers serving the airport declared that they would not transport passengers visibly carrying alcohol — in transparent duty-free shopping bags, for example. This stance stemmed from their understanding of the Koran’s ban on alcohol.

A driver named Fuad Omar explained: “This is our religion. We could be punished in the afterlife if we agree to [transport alcohol]. This is a Koran issue. This came from heaven.”

Another driver, Muhamed Mursal, echoed his words: “It is forbidden in Islam to carry alcohol.” The issue emerged publicly in 2000. On one occasion, 16 drivers in a row refused a passenger with bottles of alcohol. This left the passenger — who had done nothing legally wrong — feeling like a criminal.

For their part, the 16 cab drivers lost income.As Josh Dickey of the Associated Press put it, when drivers at MSP refuse a fare for any reason, “they go to the back of the line. Waaaay back. Past the terminal, down a long service road, and into a sprawling parking lot jammed with cabs in Bloomington, where drivers sit idle for hours, waiting to be called again.”

To avoid this predicament, Islamic taxi drivers asked the Metropolitan Airports Commission for permission to refuse passengers carrying liquor — or even suspected of carrying liquor — without being banished to the end of the line.

MAC rejected this appeal, worried that drivers might offer religion as an excuse to refuse short-distance passengers. The number of Islamic drivers has by now increased to the point that they reportedly make up three-fourths of MSP’s 900 cab drivers.

By September 2006, Muslims turned down an estimated three fares a day based on their religious objection to alcohol, an airport spokesman, Patrick Hogan, told the Washington Post, adding that “this issue has “slowly grown over the years to the point that it’s become a significant customer service issue.”

“Travelers often feel surprised and insulted,” Mr. Hogan told USA Today.

With this in mind, MAC proposed a pragmatic solution: Drivers unwilling to carry alcohol could get a special color light on their car roofs, signaling their views to taxi starters and customers alike. From the airport’s point of view, this scheme offers a sensible and efficient mechanism to resolve a minor irritant, leaving no passenger insulted and no driver losing business. “Airport authorities are not in the business of interpreting sacred texts or dictating anyone’s religious choices,” Mr. Hogan said in the USA Today interview. “Our goal is simply to ensure travelers at [the airport] are well served.” Awaiting approval only from the airport’s taxi advisory committee, the two-light proposal will likely be in operation by the end of 2006. But on a societal level, the proposed solution has massive and worrisome implications.

Namely, the two-light plan takes Muslims’ religious views into consideration for mundane commercial transactions in Minnesota. A government authority thus sanctions a signal as to who does or does not follow Islamic law. What of taxi drivers beyond those at MSP? Other Muslims in Minneapolis-St. Paul and across the country could well ask for the same religious consideration. Bus conductors might follow suit. The whole transport system could be divided between those who are observant of Islamic law and those who are not.

Why stop with alcohol? Muslim taxi drivers in several countries already balk at allowing seeing-eye dogs in their cars. Future demands could include not transporting women with exposed arms or hair, homosexuals, and unmarried couples. For that matter, they could ban men wearing kippas, as well as Hindus, atheists, bartenders, croupiers, astrologers, bankers, and quarterbacks. MAC has consulted on the taxi issue with the Minnesota chapter of the Muslim American Society, an organization that the Chicago Tribune has reported is devoted to turning America into a country run by Islamic law. The wife of a former head of the organization, for example, has explained that its goal is “to educate everyone about Islam and to follow the teachings of Islam with the hope of establishing an Islamic state.”

It is precisely the innocuous nature of the two-light taxi solution that makes it so insidious — and why the Metropolitan Airports Commission should reconsider its wrong-headed decision. Readers who wish to make their views known to the MAC can write it at publicaffairs@mspmac.org.

Mr. Pipes is director of the Middle East Forum and author of “Miniatures” (Transaction Publishers).