During their first TV debate last week, four presidential hopefuls running in the primary race of the main opposition Democratic United Party tried to project themselves as its best possible standard bearer. They also exchanged barbed words, finding fault with one another’s qualifications. Moon Jae-in, the former chief of staff for late President Roh Moo-hyun, particularly came under fire from other contenders who wanted to drag him down from his frontrunner status.

What was noticeably missing in their debate was discourse on a pile of diplomatic and security issues the nation will have to sort out, probably well into the next presidency, which begins in February 2013. They should have been made to express their concrete views about how to handle inter-Korean relations and deal with neighboring powers. Preoccupation with accusing others over their records throughout the debate appeared out of the context with the changing security situation surrounding the nation.

It does not ease our concerns that those most engaged in this are the candidates with less prospect of winning the Dec. 19 presidential election.

Rep. Park Geun-hye and software entrepreneur-turned-professor Ahn Cheol-soo, who have been neck and neck for the lead in a series of polls, have a long list of economic and social agenda but, in the eyes of many experts, lack concrete visions for ensuring peaceful and stable security environment for the nation.

Park, who was nominated as the presidential candidate of the conservative ruling Saenuri Party last week, used less than two minutes at the end of her 16-minute acceptance speech to address diplomatic and security tasks.

In Ahn’s recently published 235-page book designed to explain his views on a range of state affairs, less than 10 pages were assigned to issues related to unification, diplomacy and security.

In the ongoing discourse among presidential contenders, diplomatic and security matters have taken a back seat to ways to tighten the reins on big companies and expand welfare programs. Opposition contenders have also tried to cast the image of the ruling party candidate, a daughter of late authoritarian ruler Park Chung-hee, as incommunicative and uncompromising. She has spent the first days after her nomination shattering her negative image by paying tribute at the graves of late liberal Presidents Kim Dae-jung and Roh Moo-hyun and calling on former President Kim Young-sam who has been critical of her leadership.

Focus on social and economic agenda may be more instrumental to winning voters’ hearts. But presidential candidates should be equally or more concerned about critical security issues, calling the public attention to the external challenges the nation faces.

In her acceptance speech, Park described the current situation surrounding the country as going through an “era of crisis and anxiety.” Her statement was far from overexaggerated, considering formidable security and diplomatic challenges the next president would have to face up to during his or her five-year term in office.

North Korea’s future course still remains uncertain though its young leader Kim Jong-un, who took over from his late father Kim Jong-il in December, shows signs of moving toward reform. It would require extremely sophisticated diplomatic skills and strategic thinking to handle cooperation and disputes with China and Japan. The next president would also have to ensure that the security posture will continue to remain as strong as ever after Seoul’s planned takeover of wartime operational control from the U.S. in 2015.

Park has put forward her policy toward North Korea, dubbed the “process for trust on the Korean Peninsula,” which calls for a more sophisticated carrot and stick approach to help build confidence between the two Koreas and then bring about stable peace.

Professor Ahn, who has been courted by the DUP to field a joint front against Park, appears to have adopted North Korea policies pursued by the liberal opposition party, which would carry on Kim Dae-jung’s “sunshine” initiatives of unconditional engagement with Pyongyang. Such stance contradicts his previous remarks that he “is conservative on security and liberal on the economy.”

Both Park and Ahn, who is expected to declare his presidential bid in late September, need to set up a clear vision for handling external affairs and work out concrete measures to achieve it. For their part, voters should also ask presidential candidates to let them know about their visions and policies for the increasingly tough diplomatic and security environment.