Photos: Rand Paul's political life U.S. Sen. Rand Paul delivers remarks while announcing his candidacy for the Republican presidential nomination during an event in Louisville, Kentucky, on Tuesday, April 7. Hide Caption 1 of 20

Photos: Rand Paul's political life Paul and his wife, Kelley, wave to supporters in Louisville on April 7. Hide Caption 2 of 20

Photos: Rand Paul's political life Paul speaks in Rochester, New Hampshire, prior to meeting potential voters in March. Hide Caption 3 of 20

Photos: Rand Paul's political life Paul walks on stage before speaking at the Values Voter Summit in Washington in September. Hide Caption 4 of 20

Photos: Rand Paul's political life Paul attends a Senate Foreign Relations Committee hearing on Syria in September. Hide Caption 5 of 20

Photos: Rand Paul's political life Paul speaks at a news conference in June about the U.S. role in Syria. Hide Caption 6 of 20

Photos: Rand Paul's political life Speaking at the University of California at Berkeley in March 2014, Paul speaks on the issues of privacy and curtailing domestic surveillance. Hide Caption 7 of 20

Photos: Rand Paul's political life Paul addresses the 2014 Conservative Political Action Conference, where he easily won the presidential straw poll. Hide Caption 8 of 20

Photos: Rand Paul's political life From left, U.S. Sens. Cory Booker, Kirsten Gillibrand and Paul attend a March 2014 news conference to announce a new medical marijuana bill at the U.S. Capitol in Washington. Hide Caption 9 of 20

Photos: Rand Paul's political life In February 2014, Paul announced that he was suing President Barack Obama and top national security officials over the government's electronic surveillance program made public by intelligence leaker Edward Snowden. Hide Caption 10 of 20

Photos: Rand Paul's political life Paul leaves the Capitol in March 2013 after staging a filibuster over the nomination of CIA Director John Brennan. Hide Caption 11 of 20

Photos: Rand Paul's political life Ethics laws prevent senators from accepting payment for any job other that their duties in Washington. So Paul, a veteran eye surgeon, performs pro-bono procedures to keep current on his practice. Hide Caption 12 of 20

Photos: Rand Paul's political life Paul speaks in Bowie, Maryland, in March 2013 during a discussion on reforming the criminal justice system. Hide Caption 13 of 20

Photos: Rand Paul's political life Paul and his father speak with supporters in Ames, Iowa, before the start of a 2012 presidential campaign event. Hide Caption 14 of 20

Photos: Rand Paul's political life Paul boards an elevator after attending a Republican caucus meeting in Washington in July 2011. Hide Caption 15 of 20

Photos: Rand Paul's political life Paul unveils his own version of the federal budget during a news conference in March 2011. Hide Caption 16 of 20

Photos: Rand Paul's political life Paul speaks to hometown supporters in Bowling Green, Kentucky, during his campaign for the Senate in November 2010. Hide Caption 17 of 20

Photos: Rand Paul's political life Paul and his family celebrate his 2010 Senate victory during an election night party in Bowling Green. Hide Caption 18 of 20

Photos: Rand Paul's political life Coming from his son's soccer game, Paul wears shorts and a suit jacket while preparing for his guest spot on a Fox News television program in May 2010. Hide Caption 19 of 20