Barack Obama is an American politician who served as the 44th President of the United States from 2009 to 2017. He is the first African American to have held the office and the first president born outside the continental United States. Obama was born in Honolulu, Hawaii, and raised in Kansas and Indonesia. He attended Columbia University and Harvard Law School, where he was the first African American president of the Harvard Law Review. After graduating, he worked as a civil rights attorney and taught constitutional law at the University of Chicago Law School from 1992 to 2004. He then entered politics, serving in the Illinois Senate from 1997 to 2004. Obama was elected to the U.S. Senate in 2004 and reelected in 2008. During his first term as president, he signed into law economic stimulus legislation in response to the Great Recession, passed the Affordable Care Act, and ended military involvement in Iraq. In foreign policy, he increased U.S. troop levels in Afghanistan, reduced nuclear weapons with the United States–Russia New START treaty, and ended military involvement in the Iraq War. He ordered military involvement in Libya in opposition to Muammar Gaddafi; Gaddafi was killed by NATO-assisted forces. He also ordered the military operation that resulted in the death of Osama bin Laden. In his second term, Obama focused on domestic policy, advocating for gun control in response to the Sandy Hook Elementary School shooting, and passed the Don't Ask, Don't Tell Repeal Act of 2010 and the American Taxpayer Relief Act of 2012. He was a vocal supporter of same-sex marriage and signed the Supreme Court's decision in Obergefell v. Hodges, which legalized same-sex marriage nationwide. He advocated for the Trans-Pacific Partnership, a free trade agreement among twelve Pacific Rim countries, but withdrew the U.S. from the agreement in 2017. Obama left office in January 2017 with a 60% approval rating.