Kentucky Sen. Rand Paul announced his bid for the White House Tuesday on his website. The 52-year-old former ophthalmologist's libertarian roots sets him apart from the expansive field of Republican hopefuls, most notably in foreign policy and issues like defense spending.
His father Ron Paul, also a physician, gained notoriety in the late-1980s as a presidential nominee for the Libertarian Party, but there are signs the younger Paul is moving more mainstream Republican.
Here are five things you may not know, or remember, about Rand Paul:
He doesn't have a bachelor's degree.
Paul holds a medical degree from Duke University, but he was a few courses shy of earning a bachelor's degree from Baylor University. The Kentucky senator was enrolled at the Texas Christian college, where he studied biology and English, from fall 1981 to summer 1984. He left the program after receiving his acceptance to medical school. At the time, Duke did not require a bachelor's degree for admittance, but the policy has since changed.
A fact-check conducted by The Washington Post revealed two instances on the same day in February where Paul stated that he held degrees in biology and English. A spokesman for the senator later argued to the paper that a medical degree is a biology degree.
He worked on his father's presidential campaign while attending medical school.
Despite the demanding workload of medical school, Paul worked as a volunteer for his father, Ron Paul's 1988 Libertarian Party campaign for president. According to The New York Times, the two would hold regular debates during road trips on topics such as foreign policy and military interventions, with the younger Paul taking stances that skewed closer to Republican ideology.
His father's campaign ultimately garnered less than 1 percent of the vote.
He founded an eye care clinic to aid low-income people.
Paul founded the Southern Kentucky Lions Eye Clinic, which provides free exams and surgeries to those in need, in 1995.
The senator told National Review in 2013 that he has performed more than 100 pro bono surgeries.
"There's a philosophic debate which often gets me in trouble, you know, on whether health care's a right or not," he said at a Q&A at the University of Louisville. "I think we as physicians have an obligation. As Christians, we have an obligation. ... I really believe that, and it's a deep-held belief."
He stood on the Senate floor for nearly 13 hours during a filibuster.
In March 2013, Paul took the Senate floor for 12 hours and 52 minutes in what Slate called a "(mostly) one-man show" of a filibuster, ahead of a vote to confirm John Brennan as the director of the Central Intelligence Agency. The speech aimed to increase criticism of the Obama administration's drone policy.
Still, the diatribe was just over half the time spent by record-holder Strom Thurmond, the late South Carolina senator, who spoke for more than 24 hours nonstop in opposition to the Civil Rights Act of 1957.
He's faced multiple plagiarism accusations.
Charges of plagiarism first arose in October 2013 when MSNBC host Rachel Maddow pointed out that a portion of Paul's speech supporting gubernatorial candidate Ken Cuccinelli bore a striking resemblance to the Wikipedia page for the dystopian science fiction film Gattaca. Speaking against abortion rights activists, the senator allegedly lifted four lines from the entry.
BuzzFeed later found another similar instance where Paul recited word-for-word text from the Wikipedia entry for the movie Stand and Deliver in a June 2013 speech on immigration.
But the most damning incident occurred when The Washington Times ended the senator's weekly column after a review of his work found that he copied a passage from The Week magazine that had been published a week prior.
According to The Washington Times, Paul took some responsibility but mostly blamed the episodes on staff providing him background material that wasn't properly footnoted.