Businesses have a love/hate relationship with credit and debit cards. On the one hand, the cards boost sales and remove the risk to the merchant that they will get paid with a bounced check. On the other hand, merchants have to cough up fees that pay for everything that’s involved in keeping that payment system going. Recently, some major merchants have cheered Congress onto imposing price controls on those fees. It’s a business-to-business dispute, and politicians can’t help but insert themselves in this private fight.

Buried in the Dodd-Frank regulatory law passed last year is a provision that caps the fees that payments processors can charge merchants. In other words, Congress has taken sides, favoring some businesses (Best Buy, Target, Walgreens, Wal-Mart, etc.) over others. Merchants and banks have conflicting interests: Merchants want to pay as little as possible in fees, while banks want to charge as much as possible. What’s the correct cut for a bank to take out of a credit card or debit card transaction? I don’t know, and neither does the U.S. government. Instead, it’s properly a matter for the involved parties to settle themselves. Anything else amounts to price controls, with the attendant disorders and distortions caused by political intervention. Oddly enough, the law, which is being formulated by the Federal Reserve into regulations, targets debit card transactions and not credit card transactions, even though both involve the use of plastic to pay for goods and services. In other words, even the shape of the government intervention in the market doesn’t make any sense. Then again, that’s politics.

The Competitive Enterprise Institute has more on this development, and how one state legislative chamber–not in Minnesota, by the way–has taken a stand, telling the feds to butt out.