Joseph S. Nye Jr., a Harvard University professor and former dean of the John F. Kennedy School of Government who died Tuesday at the age of 88, was known in Japan as a longtime advocate of stronger U.S.-Japan security ties centered on an expanded military alliance and a coauthor of reports that greatly influenced the direction of the bilateral relationship.

“Professor Nye possessed profound expertise on the Japan-U.S. alliance and made significant contributions to its strengthening through dialogue and policy recommendations,” Prime Minister Shigeru Ishiba said in an official statement of condolence Thursday.

Nye, who coined the term "soft power," or the use of nonmilitary means to persuade other nations, gained notice in Japan in 1995 when, as assistant secretary of defense under U.S. President Bill Clinton, he wrote the “Nye Report.” It echoed a 1993 Clinton administration report by calling for the continued presence of 100,000 troops in the Asia-Pacific region.

This would lead to a significant revision, in 1997, of the Japan-U.S. Defense Cooperation Guidelines, which strengthened the bilateral defense relationship. The 1995 Nye Report and the 1997 guideline revisions would establish the basic direction of the relationship in the 21st century.

Between 2000 and 2024, Nye, who during his career in government had also served as chair of the National Intelligence Council, and deputy under secretary of state for security assistance, science and technology, published six reports on the U.S.-Japan alliance together with former U.S. Deputy Secretary of State Richard Armitage, emphasizing the need for closer military and defense relations, and strongly supporting Japan increasing its military capabilities in the face of a rising China and an unpredictable security situation in the Asia-Pacific region.

While welcomed by U.S. and Japanese officials, their initial call in 2000 for Japan to assume a greater defense burden and work closer with U.S. forces came at a time when many in Okinawa, where the majority of U.S. military are located, were calling for the closure of the U.S. Marine Corps air station at Futenma and demanding it be relocated outside the prefecture rather than for construction of a replacement facility in Henoko, the northern part of the prefecture.

Though the Henoko facility was eventually approved and is now under construction, it is decades behind schedule due to the longstanding opposition. No firm completion date has been announced.

Both Nye and Armitage, who died last month, supported a replacement facility for Futenma but recognized the sensitivity of the base issue in Okinawa. They recommended the overall base burden on Okinawans be eased so that the U.S. military presence is “sustainable and credible.”

By 2023, Japan had taken action along the lines of many of the Nye-Armitage reports’ recommendations. Former Prime Minister Shinzo Abe expanded the constitutional interpretation of self-defense to include collective defense with the U.S.

Another former prime minister, Fumio Kishida, promised to increase defense spending to 2% of Japan’s gross domestic product by 2027 and adopted, in 2022, a new national security plan beefing up the country’s military as well as technological, economic, and diplomatic resources.

“In the face of the threats posed by China, Russia, and North Korea, Japan’s self-defense depends more than ever on the strength of its alliances. By significantly increasing its own defense spending and pursuing closer military cooperation with the United States, the current government is moving in the right direction,” Nye wrote in a February 2023 report for Project Syndicate.

In the final Nye-Armitage report, issued last year, praise was given to Japan’s leadership for its efforts to bolster its domestic defense abilities and U.S. ties even as the authors encouraged the alliance to do more, given the great geopolitical uncertainties facing the region, and the world.

“Unlike many Western democracies, Japan has avoided the worst impulses of populism and isolationism. Its role in supporting a free and open international order grounded in the rule of law is therefore more important than ever.

“But looking ahead, the urgency of the international environment will demand more from Japan, and from the U.S.-Japan alliance,” the report said.