Barack Obama’s political rise was historic. After serving as an Illinois state senator and later a U.S. senator, he launched his presidential campaign in 2007. He defeated Hillary Clinton for the Democratic nomination and went on to defeat Republican John McCain in the 2008 election. On January 20, 2009, Obama became the 44th president of the United States and the first African American president in the nation’s history.

During his first term, Obama signed several major pieces of legislation and took important foreign-policy actions. The American Recovery and Reinvestment Act aimed to respond to the financial crisis, while the Affordable Care Act brought sweeping changes to the U.S. healthcare system. His administration also signed the Dodd-Frank financial reform law, repealed “Don’t Ask, Don’t Tell,” and confirmed Supreme Court Justice Sonia Sotomayor. In 2011, Obama announced that Osama bin Laden had been killed during a U.S. operation in Pakistan.

Obama won reelection in 2012 against Republican Mitt Romney. His second term included major developments on climate policy, immigration, veterans’ programs and relations with Cuba and Iran. He supported same-sex marriage, signed the Clean Power Plan, participated in the Paris climate negotiations and became the first sitting U.S. president to visit Cuba since 1928. The Supreme Court also ruled in 2015 that same-sex couples have a constitutional right to marry nationwide.

Obama left office on January 20, 2017, after Republican Donald Trump defeated Hillary Clinton in the 2016 presidential election. His presidency remains one of the most significant periods in modern U.S. political history, marked by historic achievements, major domestic reforms and controversial debates that continue to shape American politics.