(CNN) -- Dick Lugar, the Senate's longest-serving Republican, could become the latest political casualty in the struggle between the party's conservatives and moderates when he faces Richard Mourdock, Indiana's state treasurer, in a primary Tuesday.
Longest-serving GOP Senator Dick Lugar in political fight of his life, tells Soledad he believe he can win primary
Over 36 years in the Senate, Lugar has built a reputation as a foreign policy expert. But the longtime senator from Indiana has drawn the ire of the tea party and other conservatives who question his convictions.
He's worked repeatedly with Democrats to seek bipartisan solutions and voted for the 2008 financial bailout and President Barack Obama's Supreme Court nominees.
The result: one of the nastiest and most expensive congressional races in the nation that Democrats have gleefully called a "tea party war."
This morning, Sen. Lugar talks with Soledad and says he believes he'll win the primary and his seat in November.
"I would just say I'm the only person to finish the Capitol challenge race the last 30 years and I intend to compete again this month," Lugar says. "We're not only 80 years of age but we're still running, not only for office but physically. I'm very grateful that God has given me the strength and vigor but we have it. We want to continue to exemplify it in the service of our country, and the very best interest of all Hoosiers."
Watch the extended interview below.