The America First Citizenship and Allegiance Act establishes stricter requirements and enforcement mechanisms for naturalization and citizenship in the United States. The bill requires the Department of Homeland Security to provide English-language instruction to applicants on oath allegiance, U.S. constitutional duties, and citizenship obligations before they take the naturalization oath, with applicants required to certify under penalty of perjury that they understand and freely accept these commitments. It defines key terms broadly, including "foreign power" to encompass foreign governments, terrorist organizations, transnational criminal organizations, and cartels, and preserves the government's authority to revoke citizenship through denaturalization proceedings if applicants engaged in fraud or concealment during the naturalization process. The bill takes effect immediately upon enactment, with most provisions becoming law right away, though some specific provisions may have their own implementation timelines. Overall, the legislation affects all future naturalization applicants and expands the grounds on which the government can challenge or revoke citizenship.