CARLISLE, Pa.—President Donald Trump hosted a roundtable discussion at the Pennsylvania Defense and Innovation Summit held at the U.S. Army War College on July 15, leading talks on how best to strengthen the nation’s defenses. “The biggest names in business are all spending money in America, and they’re all spending money in Pennsylvania,” Trump said. Sen. Dave McCormick (R-Pa.), who organized the two-day summit, used the opportunity to highlight nearly $10 billion in recent investments in arms and technology industry vendors from across Pennsylvania. The investments are expected to support more than 4,000 jobs in the commonwealth. The president joined in praising Pennsylvania’s contributions to America’s arsenals....