Washington (CNN) - Republican Sen. Richard Lugar of Indiana delivered a message to Democratic Rep. Joe Donnelly who launched a challenge against him Monday, saying he's optimistic he can hold onto his seat in 2012.
"I'm very hopeful of course that our early campaigning and fundraising has brought about a situation of continuing strength in Indiana and that we'll be prepared to win the primary and general election," Lugar said in an interview set to air on CNN's "John King, USA" Monday. "I believe we would beat Joe Donnelly."
The six-term senator who is also facing a primary challenge from another Republican, Indiana State Treasurer Richard Mourdock, said there will likely be other candidates who throw their hats in the ring.
"They (the Democratic Party) believe that I might lose the primary and therefore there might be an opportunity to take over the seat," Lugar told CNN Chief National Correspondent John King. "He (Donnelly) may not be the last of those who want to participate in either the primary or the general election."
– Watch the full interview with Sen. Lugar on CNN's "John King, USA" at 7 p.m. ET Monday.