Japanese Prime Minister Shinzo Abe's historic visit to Pearl Harbour with President Barack Obama today punctuates the Obama Administration's multi-year effort to prod Japan and its neighbours in Asia to decrease tensions by moving beyond lingering war-time grievances.

But as the two leaders pay homage to the 2403 Americans who died in the surprise Japanese attack on December 7, 1941, the geopolitical backdrop for the event has been clouded by President-elect Donald Trump's pugnacious and unpredictable foreign-policy pronouncements.

During the campaign, Trump raised alarms in both countries when he questioned the value of the US military's basing agreements in Japan and suggested the island nation consider developing its own nuclear weapons.

Abe is set to become the first Japanese leader to take part in a ceremony at the USS Arizona Memorial, which honours the American sailors and Marines who perished aboard the battleship 75 years ago. The trip, in the works before Trump's election last month, is intended as a symbolic bookend to Obama's visit in May to Hiroshima, where the United States deployed the world's first atomic bomb.


Like Obama, Abe does not plan to apologise for Japan's sneak attack, which wounded an additional 1178 and prompted the United States' entry into World War II. Rather, he will reflect on history "and renew the determination of the Japanese people not to repeat the devastation of war," said Tamaki Tsukada, spokesman for the Japanese Embassy in Washington.

US military veterans are expected to take part in a ceremony that will be "a powerful demonstration of how the two countries can overcome a very painful history to become the closest of allies and friends," Daniel Kritenbrink, the White House's senior director for Asian affairs at the National Security Council, told reporters.

Abe's visit marks another delicate step towards broader regional reconciliation in Asia, though it is unlikely to satisfy demands in South Korea and China that the Japanese Government formally apologise and atone for war-time atrocities. Three of Abe's predecessors, including his grandfather, Nobusuke Kishi, a former Prime Minister, purportedly visited Pearl Harbour in the 1950s, but none took part in a ceremony to pay homage to the dead over concerns about right-wing political opposition in Japan.

Such a visit seemed unlikely as recently as three years ago when Abe, leader of the conservative Liberal Democratic Party, visited Tokyo's Yasukuni Shrine, the paean to Japan's war-time dead, in a move that inflamed regional tensions and irritated the White House. The Obama Administration has sought to improve relations in Asia, especially between US allies Japan and South Korea, to hedge against China's rise and address shared challenges, such as a nuclear-armed North Korea.

Since then, Tokyo has negotiated, with support from the White House, a resolution with Seoul over the forced use of women as sex slaves by Japan's imperial army. And Abe expressed remorse for the war during remarks to a joint meeting of the US Congress last year ahead of the 70th anniversary of the end of World War II.

Obama's speech in Hiroshima was well received in Japan, prompting Abe to pursue the reciprocal visit. Obama is in Hawaii on holiday.