Gov. Terry Branstad is preparing the state for a federally mandated health exchange even though he opposes President Barack Obama’s signature law and hopes the U.S. Supreme Court invalidates it. The Republican governor says Iowa should proceed with a state-run exchange only if the controversial law is upheld. The U.S. Supreme Court will rule Thursday on the federal law, which seeks to extend coverage to the nation’s uninsured. Democrats who control the Iowa Senate say they will push for a state health-benefit program regardless of how the court rules, while leaders in the Republican-led House say the state has already enacted pieces of the law in a way that’s tailored to Iowa. A report from the U.S. Census Bureau says 366,000 Iowans are uninsured, roughly 12 percent of the population.