It seems that a pressing issue has just popped onto Congressman Anthony Weiner’s radar screen — chain stores replacing mom-and-pop small businesses, a trend dating back to at least the 1950s and 1960s of Wal-Mart and McDonald’s. Mr. Weiner put out a study yesterday showing that chain pharmacies are pushing out independent drug stores. According to the study, the city has since 1990 lost 447 small pharmacies and gained 434 chain pharmacies.

While a net loss of 13 pharmacies may seem insignificant, Mr. Weiner sees a crisis. His solution is to introduce legislation giving independent pharmacies a small edge over chain pharmacies when it comes to Medicaid reimbursement. But what would be the reason to fiddle with the free market? If chain drug stores succeed in New York, it can only be because New Yorkers have voted with their feet and their wallets. CVS, Rite Aid, and Duane Reade must be offering something the customers like.

As with all chains, what they offer is information. A brand like CVS, McDonald’s, or Barnes & Noble tells consumers what they’ll be getting there. Consumers like that the McDonald’s hamburger they eat in Queens will be the same as the one in Manhattan. The same is true of the service, selection, and prices they find at chain drug- stores. A study cited by independent drug store owners shows their shops offering lower prices on prescription drugs. Maybe they’re not charging enough to stay afloat. If the small drug stores can win in the market, all the best to them. But New Yorkers don’t need our politicians knee-capping the winners with whom most of us have chosen to shop.