We should dispense with the notion that the credit card business in the United States is a free market with robust competition. Possibly the most telling statistic tracks the difference between borrowing benchmarks, such as the prime rate, and what you pay on your credit card. Make no mistake, your bank is cranking up credit card rates faster than any overall increase. Credit cards are a major source of credit for small businesses, at an increasingly dear cost. Fortunately, Trump has endorsed — via social media — bipartisan legislation, the Credit Card Competition Act, that would crack open the Visa-Mastercard duopoly by allowing merchants to route transactions over competing networks.