ASHINGTON—The U.S. criminal investigation into the Jan. 6 Capitol riot is entering a more contentious phase as it nears the one-year mark, with initial trials set to test the government’s strategy of using provisions first laid out in a 2002 financial-industry law to prosecute some accused... ...prosecutors searched for tools to elevate some of the cases beyond the misdemeanor charges often applied for unruly but far less momentous Capitol protests. They turned to a provision in the 2002 Sarbanes-Oxley Act, enacted after the accounting-fraud scandal and collapse of Enron, which imposes a potential 20-year sentence on those convicted of obstructing...