He served three terms representing the 13th District in the Illinois Senate from 1997 to 2004, running unsuccessfully for the United States House of Representatives in 2000. In 2004, Obama received national attention during his campaign to represent Illinois in the United States Senate with his victory in the March Democratic Party primary, hiskeynote address at the Democratic National Convention in July, and his election to the Senate in November. He began his presidential campaign in 2007, and in 2008, after a close primary campaign against Hillary Rodham Clinton, he won sufficient delegates in the Democratic Party primaries to receive the presidential nomination. He then defeatedRepublican nominee John McCain in the general election, and was inaugurated as president on January 20, 2009. Nine months later, Obama was named the 2009 Nobel Peace Prize laureate.
He was re-elected president in November 2012, defeating Republican nominee Mitt Romney, and was sworn in for a second term on January 20, 2013. Early in his first term in office, Obama signed into law economic stimulus legislation in response to the Great Recession in the form of the American Recovery and Reinvestment Act of 2009 and the Tax Relief, Unemployment Insurance Reauthorization, and Job Creation Act of 2010.
Other major domestic initiatives in his presidency include the Patient Protection and Affordable Care Act, often referred to as Obamacare; theDoddFrank Wall Street Reform and Consumer Protection Act; the Dont Ask, Dont Tell Repeal Act of 2010; the Budget Control Act of 2011; and the American Taxpayer Relief Act of 2012. In May 2012, he became the first sitting U.S. president to publicly supportsame-sex marriage and in 2013 his administration filed briefs which urged the Supreme Court to strike down the Defense of Marriage Act of 1996 and Californias Proposition 8as unconstitutional. In foreign policy, Obama ended U.S. military involvement in the Iraq War, increased troop levels in Afghanistan, signed the New START arms control treaty with Russia, ordered U.S. military involvement in Libya, and ordered the military operation