Billionaire casino magnate Sheldon Adelson, whose record-breaking campaign spending in 2012 made him an icon of the new super-donor era, is leveraging that newfound status in an escalating feud with industry rivals over the future of gambling. Adelson, best known for building upscale casino resorts in Nevada and more recently in Asia, wants to persuade Congress to ban Internet betting. He says the practice is a danger to society and could tarnish the industry’s traditional business model.