Barack Obama served as the 44th President of the United States from January 20, 2009, to January 20, 2017. A member of the Democratic Party, he previously represented Illinois in the U.S. Senate from 2005 to 2008 and served in the Illinois State Senate from 1997 to 2004. Obama is known for his signature policies including the Affordable Care Act, also known as Obamacare, and his efforts in economic recovery following the 2008 financial crisis. His presidency was marked by significant legislative achievements and a focus on healthcare reform, climate change, and foreign policy initiatives such as the Iran nuclear deal.