Graham, 60, has served in the U.S. Senate since 2003. Before that, he served as a member of the House of Representatives for eight years.
During his campaign kick-off speech in June, Graham said the Untied States will “never enjoy peaceful coexistence with radical Islam,” adding that “security through strength” is necessary for the country to be safe.
Graham has criticized President Barack Obama, stating that Obama made the United States “less safe.” He also said the greatest threat to the world is Iran acquiring a nuclear weapon.
Graham is known as an outspoken Republican who is not afraid of getting into disagreements with opponents, even within his own party. He believes in a strong military and is close to Sen. John McCain, R- Ariz., who ran against Obama for president in 2008.
Graham recently retired from the Air Force Reserves after 33 years of military involvement, where he was promoted to the rank of colonel.