Obama's nuclear tightrope

President Obama leaves Thursday on an extensive diplomatic tour of Asia with a busy schedule of meetings during nine days in Japan, Singapore, China, and South Korea.

But not on his itinerary is a stop in either Hiroshima or Nagasaki, where the US dropped atomic bombs at the end of World War II.

The mayors of the two Japanese cities had invited him, noting that Obama has pledged to pursue a world free of nuclear weapons and was awarded the Nobel Peace Price. But such a visit -- the first by an American president in office -- would be highly controversial and would inflame Obama's critics who accuse him of apologizing too much for the sins of US foreign policy.

Obama, however, did tell Japanese TV network NHK on Tuesday that he would like to eventually go to Hiroshima and Nagasaki sometime during his presidency -- he just couldn't fit it into his schedule this time.

"The memories of Hiroshima and Nagasaki are etched in the minds of the world and I would be honored to have the opportunity to visit those cities at some point during my presidency," Obama said in the interview.