This report is divided into three major sections analyzing Cuba's political and economic environment, U.S. policy, and selected issues in U.S.-Cuban relations. Legislative initiatives in the 114th Congress are noted throughout the report, and four appendixes provide a listing of enacted measures (Appendix A), bills receiving some action in 2015 (Appendix B), bills seeing action in 2016 (Appendix C), and additional bills and resolution this Congress (Appendix D).

This report provides an overview of challenges by states to federal officials' alleged failure to enforce provisions of immigration law. It begins by discussing (1) the lawsuits filed by six states in the mid-1990s; (2) Arizona's counterclaims to the federal government's suit to enjoin enforcement of S.B. 1070; and (3) Mississippi's challenge to the Deferred Action for Childhood Arrivals (DACA) initiative. It then describes the challenge brought by over 25 states or state officials in December 2014 to the Obama Administration's proposal to expand DACA and create a similar program for unauthorized aliens whose children are U.S. citizens or lawful permanent resident aliens (LPRs) (commonly known as DAPA).

This report discusses new FDA guidance regarding blood donations from sexually-active gay men. Since the 1980s, the Food and Drug Administration (FDA) has recommended that men who have sex with men (MSM) be indefinitely deferred (i.e., permanently banned) from donating blood. This action was taken to help control the spread of the human immunodeficiency virus (HIV) through the blood supply.

This report discusses the current status of Pakistan's nuclear arsenal, which probably consists of approximately 110-130 nuclear warheads. Chronic political instability in Pakistan and Islamabad's military efforts against the Taliban and al-Qaeda have raised concerns about the security of the country's nuclear weapons. Some observers fear that Pakistan's strategic nuclear assets could be obtained by terrorists or used by elements in the Pakistani government; however, U.S. officials have generally expressed confidence in the security of Pakistan's nuclear weapons.