He had worked closely with his predecessor, Seiji Maehara, and fully shared Maehara’s view of U.S.-Japan relations as “the cornerstone” of Japanese foreign policy, he assured me and Post correspondent William Wan during an interview Friday afternoon. The disastrous March11 earthquake and resulting nuclear accident weren’t going to distract Japan from its international responsibilities, he said; on the contrary, Japan will rebuild and emerge “to play an even greater role in the international community.” In dealing with China, Matsumoto told us, Japan will work closely with the United States and the nations of Southeast Asia.

All of this might sound like boilerplate, except that when Matsumoto’s Democratic Party of Japan took power in 2009 — ending a half-century of rule by the conservative Liberal Democratic Party — none of it could be taken for granted. Leading DPJ officials, including its first prime minister, Yukio Hatoyama, and power broker Ichiro Ozawa, flirted with a realignment of Japanese policy toward China and away from the United States. Top figures questioned the worth of the U.S.-Japan alliance and the need for U.S. troops based in Japan.

Maehara, who was forced by a pseudo-scandal to resign just before the earthquake, was a key figure in tugging Japan back toward its traditional alliance with the United States. China itself played an even more important role: by bullying Japan over some disputed islands and playing mercantilist games with exports of key resources, the Communist government reminded Japan of its unreliability. And U.S. assistance following the earthquake, with American armed forces playing an especially active role, seems to have sealed the deal: the worth of the alliance took on concrete form.

Now Matsumoto presents those early days as nothing but a misunderstanding. “Perhaps the problem was more with the DPJ itself,” he told us Friday. “We have always been aware that the U.S.-Japan relationship was the cornerstone. But as newcomers, the DPJ should have explained more to the outside world what it had taken for granted.”

Meanwhile, the foreign minister hopes that the outside world will get over a mistaken impression of its own — that Japan is a dangerous place to visit. Tourist and business visits were off by two-thirds or more in March, he said, even though Japan is safe, beyond a narrow belt around the Fukushima nuclear plant. Japan is “open for business,” he said. And if that message does not get out, “it would be a huge loss for Japan, but not only that. If the world economy has to grow without Japan as a full partner, that would be a loss for the world as well.”