Years of bloody conflict between Japan and the United States led to amicable reconciliation; war between them now is inconceivable.
The transformation of countries from enemies to allies may be attributed to changes in national interest, but there is something else at work, and that is change at the level of the people themselves.
There are two basic approaches to preventing war. One is based on arrangements of power, on creating alliances or collective security systems that deter war through their military strength. The other is affecting the attitudes of people so they no longer perceive one another as enemies.
After the Second World War, we constructed a series of alliances to deter war. The successful end of the Cold War is frequently attributed to our policy of containing Soviet expansionism through our alliances.
But deterrence does not always work. In 1941, the Japanese were under no illusions about the United States' militarily superiority.
"I can guarantee to put up a tough fight for the first six months," the Japanese navy's commander-in-chief, Isoroku Yamamoto, told the prime minister in 1940, "but I have absolutely no confidence as to what would happen if it went on for two or three years."
Yamamoto's assessment may have been influenced by the time he spent in the United States, notably studying English at Harvard. Indeed, his desire to avoid war made him suspect in the eyes of other Japanese. "Yamamoto's got no guts," a junior naval officer mocked. "He's too fond of England and America."
When his political superiors decided on war, Yamamoto obeyed, but his conflicted role in masterminding the Pearl Harbor attack raises a question. If there had been more Japanese who had spent time here, studying not just English but subjects that would allow more interaction with Americans for a longer period, could Pearl Harbor have happened?
In the aftermath of the Second World War, this second approach to avoiding war was the foundation of the European Union. The idea was to knit together countries that had been enemies so that they would no longer be willing to contemplate war.
One of the products of this approach is the Erasmus student exchange program. The hope is that students with international experiences will not go to war. Thus, the Erasmus student network seeks to promote "love for Europe as an area of peace and cultural exchange."
This alternative approach to preventing war is particularly important now with the rise of China. The Department of Defense, in a recent report to Congress, has stressed the need to deter conflict with China "through force posture, presence, actions to strengthen alliances and partnerships, and capability developments."
Unlike the situation during the Cold War, the Chinese send more students here than any other country. This surge in Chinese students is not only a tremendous compliment to the quality of American higher education; it is also a political signal. By expressing a willingness to learn from others, they are demonstrating a willingness to change. Whatever the tensions that exist now, especially concerning human rights, the growing number of Chinese students here is a reassuring sign of hope for the future. As one Chinese student put it during a Thanksgiving dinner at Georgetown University, she is "thankful for the opportunity to study and live here."
We now have a choice. We can attempt to preserve peace through the traditional means of balance of power and alliances, through the forward positioning of our military forces. But those who would rely on such means need to explain why the Chinese, rather than being deterred, came right at us in Korea in 1950.
Whatever the success of deterrence in Europe, its record in Asia has been much more problematic, raising the question of whether a different approach to preventing war might be desirable.
Wars begin in people's minds. That is why the communists, whether in the Soviet Union or China, did not allow their students to come here in large numbers: They did not want them to be corrupted by our views of democracy and the rule of law.
The situation now is different, and we have an opportunity that did not exist before, which we should seize.
There are no guarantees. Even so, as December 7 and the 69th anniversary of Pearl Harbor approach, we should contemplate the implications of the Yamamoto question and ask what makes countries enemies — and what can transform them into friends.