Mr Barack Obama's two terms in office have been marked by several pioneering forays.

No American president had visited Cuba in nearly 90 years. Mr Obama did. None had visited Myanmar. He has gone twice.

Few saw merit in negotiating with Iran's autocratic mullahs. Mr Obama struck a nuclear deal with the Iranians that he ranks among his greatest accomplishments. And in Vietnam this week, he lifted a decades-old embargo on military sales.

With each decision, critics complained that he rewarded autocrats or upset allies. He remains defiant.

And although he did not apologise for the bombings of Hiroshima and Nagasaki, with no election left for himself, he cares far less that any remorse he expresses for the loss of life there will be included in what opponents have caricatured as an "apology tour" of foreign cities. Even in Tokyo, there is some ambivalence about Mr Obama's visit. Prime Minister Shinzo Abe is expected to get a political lift, and ordinary Japanese have embraced Mr Obama's support for nuclear disarmament. But the policy establishment is not keen to be drawn into a fresh debate over history, and some worry Mr Abe may come under pressure to visit Pearl Harbor in return.

THE NEW YORK TIMES