Question

what was one national security policy the united states established during the covid - 19 pandemic?
limited travel to the united states
restricted emigration from the united states
passed a new law called the patriot act
formed a new department of the federal government

Explanation:

During the Covid - 19 pandemic, the US limited travel to prevent the spread of the virus, which is a national - security - related measure. The Patriot Act was passed after 9/11 and not related to Covid - 19. There was no major new federal department formed specifically due to Covid - 19 as a national security policy, and restricting emigration from the US was not a major national security policy during the pandemic.

Answer:

limited travel to the United States