Protect America First Act This bill temporarily bars noncitizens from entering the United States and addresses related issues. During the four-year period starting from this bill's enactment, any alien who unlawfully enters the United States at a port of entry without proof of citizenship shall be inadmissible. The bill requires the detention of certain aliens (generally, those not legally present in the United States) who have been charged with any crime resulting in the death or serious bodily injury of another. Furthermore, a state or local government shall be ineligible for certain federal assistance if that government has a law or policy that (1) violates certain laws about sharing immigration status information with federal officials, or (2) prohibits law enforcement from obtaining immigration status information from any individual. The bill also requires (1) the Department of the Treasury to establish a fund for a barrier along the U.S.-Mexico border, and (2) the Department of Homeland Security to construct such a barrier by December 31, 2021. The bill also reinstates certain immigration-related executive orders, including an order that generally barred nationals of certain countries (such as Somalia and Sudan) from entry, while rescinding other orders, including an order promoting access to voting for individuals legally entitled to vote. The bill also rescinds orders establishing the Deferred Action for Childhood Arrivals (DACA) and Deferred Action for Parental Accountability (DAPA) programs. (Generally, DACA defers the deportation of eligible aliens who entered the United States as minors, while DAPA is a similar program for the alien parents of U.S. citizens or permanent residents.)