[cnn-photo-caption image= http://i2.cdn.turner.com/cnn/2008/images/07/16/art.bayhnunn.gi.jpg caption="Nunn and Bayh are joining Obama Wednesday."]
(CNN) - Who Obama is campaigning with Wednesday just might get more attention than what the presumptive Democratic presidential candidate says.
The Illinois senator is set to be joined on the trail by Indiana Sen. Evan Bayh and former Georgia Sen. Sam Nunn - two Democrats widely believed to be on the shortlist for the vice presidential spot.
Election Center: Who's on Obama's shortlist
The two are set to join Obama at Purdue University in West Lafayette, Indiana for a discussion on national security issues - a forum that is designed to set to stage for the Democratic president candidate's overseas trip next week.
Specifically, the three are set to discuss nuclear non-proliferation, bioterrorism, cyber security and emerging national security threats.
Bayh, who comes from a powerful Indiana family and once served as governor of the state, remains a very popular figure there. His aggressive campaigning on behalf of Hillary Clinton during the state's Democratic primary is widely seen as a chief factor for the New York senator's narrow victory there. He briefly flirted with his own presidential bid late last year but ultimately ruled against it.
Nunn remains one of the most respected national security and foreign policy experts on the national scene. The former senator has a serious, no-nonsense demeanor that would add instant gravitas to the ticket, and he is a popular figure in Georgia - a state the Obama campaign hopes to make competitive this cycle.
Both Nunn and Bayh have remained tight-lipped when it comes to the VP slot, though Bayh did acknowledge last month he would take the position if asked.
"I don't think it's the kind of thing you say no to…the answer to that is yes," he said in June. "If you care about serving your country, that is the kind of thing that you do,"