Barack Obama was the 44th president of the United States, and the first African American to hold the office. He was born in 1961 in Hawaii to a mother from Kansas and a father from Kenya. After attending Columbia University and Harvard Law School, he worked as a community organizer, civil rights lawyer, and university lecturer. He also taught constitutional law at the University of Chicago Law School from 1992 to 2004. He served three terms in the Illinois Senate from 1997 to 2004, and was elected to the U.S. Senate in 2004. In 2008, he won the Democratic Party's presidential nomination, and went on to defeat Republican nominee John McCain in the general election. As president, Obama signed into law the Affordable Care Act, a major healthcare reform law. He also signed the Dodd-Frank Wall Street Reform and Consumer Protection Act, which instituted new regulations on the financial industry. He also ordered U.S. military involvement in the war in Afghanistan and the assassination of Osama bin Laden. In his second term, he worked to implement the Deferred Action for Childhood Arrivals program, and negotiated the Joint Comprehensive Plan of Action, an international agreement on the Iranian nuclear program. He also sent American troops to fight the Ebola virus outbreak in West Africa. Obama left office in 2017, and was succeeded by Republican president Donald Trump.