The United States has maintained significant interest in Mexico, an ally and top trade partner. In recent decades, U.S.-Mexican relations have grown closer through cooperative management of the 2,000-mile border, the North American Free Trade Agreement (NAFTA), and security and rule of law cooperation under the Mérida Initiative. Relations have been tested, however, by President Donald J. Trump’s shifts in U.S. immigration and trade policies. This book provides an overview of political and economic conditions in Mexico, followed by assessments of selected issues of congressional interest in Mexico: security and foreign aid, trade, immigration, organized crime, violence and water issues.