You couldn't ask for better timing. As President-elect Donald Trump sets up his administration, and as Tokyo marks its six-decade-long membership in the United Nations, Japan should press its case for a permanent seat on a reformed Security Council it envisions, a former U.S. official has said.

"Japan would have to take a lead and make a real concerted private, as well as public, effort to engage early and strongly and kind of become the spokesman for the expansion group," Shirin Tahir-Kheli said in a recent interview at her Philadelphia home.

She was referring to efforts by Japan, Brazil, India and Germany, collectively known as the Group of Four. They have been pushing for additional permanent and nonpermanent council seats in the body, which currently has 15 members.