The mechanism: Visa's 60%+ share of U.S. debit processing was never really a technology win — it was built on merchant and issuer routing contracts that, per the DOJ's own September 2024 complaint, foreclose at least 45% of U.S. debit transactions from competition and insulate roughly 75% of Visa's total debit volume from rivals. A federal judge in the Southern District of New York rejected Visa's motion to dismiss in June 2025, meaning the Sherman Act monopolization case is live and headed toward discovery. Layer on top the Durbin Amendment fight: a district court already ruled the Fed's Regulation II interchange cap exceeded its statutory authority, and in January 2026 the Credit Card Competition Act — which would force big issuers to offer a non-Visa/Mastercard routing option on credit, not just debit — was reintroduced with an unusual assist: a Trump endorsement on Truth Social. None of this is about a new tap-to-pay feature. It's about whether Washington lets Visa keep routing the way it always has.