“I will take his remarks seriously when he is elected president,” said Kuni Miyake, head of the Foreign Policy Institute in Tokyo.

“Media overreaction creates people like Trump, who represent the dark side of the US,” he added. “I believe in the western democracies — in the end they’ll come up with a healthy outcome.”

But Tokyo is realizing that even if Mr Trump loses, his rhetoric is seeping into the popular consciousness, and other US politicians are changing their positions in response.

Japan regards the US military presence as crucial to its long-run security position given China’s rise, and counts on the US nuclear umbrella to deter attack by the regime in North Korea.