Senate Republicans are urging major credit card companies to reverse the decision to categorize gun purchases separately. Sen. Roger Marshall, R-Kansas, is leading a group of 12 GOP senators demanding that the CEOs of Visa, Mastercard and American Express monitor gun store sales. The companies recently announced that they will apply the International Organization for Standardization’s new dealer category code to gun store sales. Trades in firearms stores were previously classified as “general merchandise.” In a letter obtained exclusively by FOX Business, Republican lawmakers argue that complying with the dealer code could open a backdoor gun control registry that would affect law-abiding firearms owners. “This decision, which is already being hailed by radical anti-gun activists, is the first step toward bringing backroom gun control to law-abiding Americans,” the senators wrote to the CEOs. “Any change that seeks to affect the ability of a United States citizen to legally purchase a firearm belongs to Congress, not the payment networks, international standard-setting organizations, or financial institutions that some of you serve.” VISA, MASTERCARD, AMEX TO SEPARATELY CLASSIFY GUN STORE SALES Sen. Roger Marshall, R-Kansas, is leading a group of 12 GOP senators demanding that the CEOs of Visa, Mastercard and American Express monitor gun store sales. (Getty Images) Merchant category codes are not exclusive to gun store sales, as codes exist for almost every type of purchase, including those at supermarkets, clothing stores, coffee shops, and other retailers. But the codes only indicate the type of merchant at which the credit or debit card is used, not the specific items. This means that an item like a gun safe, for example, could be marked as a big buy at a gun store, as it can be purchased for thousands of dollars. “Due to the nature of the information collected by merchants when processing a transaction, you will not have the ability to know what is being purchased. Therefore, the purported benefits of detecting suspicious purchases steadily decline,” Republicans wrote. “Given this, it is clear that these changes are being pushed for far more nefarious reasons and are likely to be just the first step with calls for a blanket denial of gun sales processing to come in the near future.” According to the letter, ISO is a voluntary organization that cannot unilaterally determine how business is conducted. “To be absolutely clear, your hand is not being forced,” the lawmakers wrote. “Establishing a new dealer code for gun transactions is a choice each of your companies makes. You are choosing the side of gun control advocates over the privacy and Second Amendment rights of millions of law-abiding Americans.” “You are choosing to enter this political debate – which should only take place at the ballot box and in Congress – and by doing so you are making it clear that you are more than impartial network operators seeking to maximize value for your customers and shareholders You have become anti-gun activists yourselves, knowingly or not,” they continued. DEMOCRATS DEMAND ANSWERS AS CREDIT CARD COMPANIES PUSH TO MONITOR GUN PURCHASES Credit card companies recently announced that they will apply the International Organization for Standardization’s new commercial code to gun store sales. Trades in firearms stores were previously classified as “general merchandise.” (iStock) Republicans told the CEOs that Congress will have no choice but to intercede on behalf of law-abiding American gun owners if their companies insist on tracking gun store sales. The senators also sought answers from the credit card companies on a number of issues related to the new labeling of gun purchases, including their understanding of the ISO process, their input into the ISO, coordination with outside entities such as activist organizations or politicians. how the information will be used to curb suspicious firearms sales and how to ensure the financial privacy of law-abiding customers. Gun control activists argued that a separate category for gun store sales would help identify suspicious amounts of firearms sales that could potentially lead to mass shootings. A week before the 2016 Pulse Nightclub massacre in Orlando, Florida, the gunman bought more than $26,000 worth of guns and ammunition using credit cards. New York City officials had pressured the ISO and banks to adopt the new gun sales code. Smith and Wesson handguns are on display during the NRA Annual Meeting & Exposition at the Kay Bailey Hutchison Convention Center on May 5, 2018 in Dallas, Texas. (Photo by Justin Sullivan/Getty Images/Getty Images) “These credit card companies must now take the next step and flag suspicious transactions in gun and ammunition sales just as they do for fraud and money laundering,” New York State Attorney General Letitia James said in a recent tweet. “By working together and using the tools at our disposal, we will help protect our communities and save lives.” CLICK HERE TO READ MORE ABOUT FOX BUSINESS The senators’ letter comes days after House Republicans sent credit card companies a similar request for answers about tracking sales at gun stores. “A gun control advocate might view any desire to own or acquire a firearm as inherently suspect,” the House members wrote at the time. “Rather, this is a transparent attempt to relax the exercise of constitutionally protected rights and circumvent existing legal restrictions on the government’s creation of firearms registries.”