Former President George W. Bush on Thursday outlined plans to establish a $300 million library, museum and research institute, taking a step back onto the national stage. The George W. Bush Policy Institute—which would be the first think tank to be affiliated with a presidential library—will address issues that were priorities during Mr. Bush's presidency, such as education, global health, political freedom and economic growth, and seek to promote advances by offering practical solutions, the former president said. In a speech at Southern Methodist University in Dallas, where the center is slated to be built, Mr. Bush said the institute...