Beginning September 13, New York City will be the first major city to require proof of vaccination to enter indoor dining, gym, and entertainment venues. But is it legal? Jennifer L. Piatt, a research scholar at Sandra Day O'Connor College of Law and the deputy director, Western Region Office of the Network for Public Health Law, joined Cheddar to explain that it likely has firm footing. "My thoughts are: this policy is grounded in the law," she said, describing the 1905 Supreme Court case that established police powers for the state in regulating public health. While the U.S. already is seeing challenges to vaccine mandates, Piatt noted that they were largely being upheld in courts and said she expects the trend to continue going forward.