The $240 billion U.S. gambling industry is looking to bolster its political influence with a national effort to mobilize workers behind its policy agenda heading into the 2016 elections. The American Gaming Association (AGA), a trade group representing mainly casinos and lotteries, boasts a growing membership covering 40 states, and the trade group’s leadership vowed Wednesday to increase its clout in Washington, despite the loss of retiring Sen. Harry Reid (D-Nev.), an influential congressional ally. “We’re going to be more active in political discussion,” MGM Resorts International CEO Jim Murren told reporters Wednesday at the AGA’s shiny new D.C. digs....