The government could force people to stay put. It could even force American citizens who show no signs of the disease to stay away from the public. It’s the power to quarantine, and it comes from laws authorizing dramatic, sometimes drastic action in order to avoid a true public health crisis.

The power is scattered among different agencies, spanning federal, state, and local governments. The CDC, for example, has limited authority to quarantine during international and interstate travel under section 361 of the Public Health Service Act. That provision authorizes the U.S. Secretary of Health and Human Services to “take measures to prevent the entry and spread of communicable diseases from foreign countries into the United States and between states.” President George W. Bush designated Ebola as one of these communicable diseases in 2003 in an executive order.

But historically it hasn’t been the CDC that issues quarantine orders. It’s state health departments. As the CDC’s website states, laws “can vary from state to state and can be specific or broad. In some states, local health authorities implement state law. In most states, breaking a quarantine order is a criminal misdemeanor.” To make sure the quarantine is effective, local officials can send law enforcement to check in or opt for occasional visits from health workers.