Politico – Billionaire casino mogul Sheldon Adelson’s mission to ban Internet gambling just got a major opponent — a coalition backed by MGM International and other Washington powerhouses. The newly minted Coalition for Consumer and Online Protection is going up Wednesday with an initial three-week, $250,000 online and print ad buy to campaign against a federal online gambling ban. The ad buy is focused predominately on the Washington, D.C., market, but also will have presence in Nevada. The coalition has also hired some heavy hitters to help them make their case. Former Rep. Mike Oxley (R-Ohio), who served as Financial…