U.S. Sen. Lindsey Graham announced his candidacy for president Monday from his childhood home in South Carolina. Mandel Ngan/AFP/Getty Images

U.S. Sen. Lindsey Graham announced his candidacy for president Monday from his childhood home in South Carolina, the “First in the South” primary state that is seen as an important contest for Republican hopefuls in the early nominating process. A former Air Force lawyer, Graham adds a hawkish foreign policy background to the contest, and has come out in favor of policies that many of his competitors have shied away from, including a pathway to citizenship for the estimated 11 million undocumented immigrants in the country.

Graham was elected to the Senate in 2002, and served in the House of Representatives for eight years before that. He’s seen as an underdog in the contest and barely registered in a recent poll of Iowa voters. He joins three Senate colleagues in the race, including Republicans Marco Rubio, Rand Paul and Ted Cruz.

As a senator, Graham has taken many trips to Iraq and Afghanistan, experiences he is expected to rely on heavily during his campaign, in contrast to others, like Paul, who have been critical of American involvement in those countries.

Graham has a long history of winning difficult election contests. In 22 years, he hasn’t lost an election. In 2014, he was the target of a tea party primary attack and came away unscathed, easily winning re-election.

Broadly, he is seen as a moderate in the Republican field on domestic policy. He is more likely to work across the aisle in the Senate to move bills through with Democrats. In addition to supporting immigration reform, he is also more open to spending than many of his Republican colleagues. On the subject of Islamic militants, he is known for his aggressive nature, saying of those who join terror groups that he wouldn’t call a judge for those individuals, he would “call a drone, and we will kill you.”

Graham, 59, is the only unmarried candidate in the field. He grew up in South Carolina and was the first member of his family to graduate from college. His parents owned a pool hall and restaurant that he worked in as a youth.