President Joe Biden has vowed to reopen most U.S. schools in his first 100 days. But that could ignite clashes among teachers, their unions and parents over how to do that safely. Petitions and potential teacher strikes loom, even while parents watch children struggle online. Nic Querolo reports that the issue has been one of the toughest pandemic challenges for local policymakers.See omnystudio.com/listener for privacy information.