South Korea and Japan reached the landmark agreement on the "comfort women" issue of wartime sexual slavery out of their own "self-interest" amid a need for cooperation to cope with North Korean threats, former U.S. Under Secretary of State Wendy Sherman said.

Sherman made the case in a recent article contributed to CNN, as she called for U.S. President Barack Obama to visit Hiroshima for the first time as a sitting American president since the U.S. dropped a nuclear bomb in the Japanese city.

She also said that Germany's path of post-war reconciliation with neighbors was "one of self-interest," adding that West Germany's first post-war chancellor, Konrad Adenauer, established common cause with former-enemy France as the two countries joined arms to face the Soviet threat.

"Recently, we have seen self-interest at work in Japan as well. Concerned with increased provocations and rising tensions in their backyards -- particularly from North Korea -- Japan and South Korea have finally come to a resolution of the 'comfort women' issue, a painful chapter of World War II," Sherman said. 

In late December, Seoul and Tokyo reached the deal that centers on Japan's admission of responsibility for the wartime crime and plans to pay reparations to the victims. South Korea promised to end the dispute once and for all if Japan fulfills its responsibilities.

Sherman said the agreement will help them forge a united front amid security threats.

She also said that the most significant part of the agreement was the "commitment by Japan and South Korea to remembrance -- to not hiding the past when writing textbooks for the next generation."

"The political courage of Japanese Prime Minister Shinzo Abe and South Korean President Park Geun-hye should make President Obama's decision an easy one," Sherman said. "He should go to Hiroshima, not to apologize, but to serve our interests by showing allies in the region that we are willing to acknowledge the past in order to focus on the future."

Whether Obama would visit Hiroshima next month on the sidelines of a summit of Group of Seven leaders has been a focus of attention since Secretary of State John Kerry made a historic visit to the city earlier this month and said he would convey to Obama what he saw in Hiroshima and "how important it is at some point to try to get here." (Yonhap)