TOKYO -- When rising temperatures threatened a catastrophe at the tsunami-hit Fukushima Daiichi nuclear plant days after a devastating earthquake in March 2011, then-Prime Minister Naoto Kan finally decided to deploy the Self-Defense Forces.
He ordered SDF helicopters to fly over the plant to spray water over a heating reactor. Seeing Japan's struggle, U.S. forces stationed in Japan decided to jump in, setting in motion a rescue effort, dubbed Operation Tomodachi, after the Japanese word for "friend."
Commenting on the 10th anniversary of the disaster, Pentagon press secretary John Kirby called the U.S. support "a testament to the strength of our alliance" and to "the strength of our friendship with the Japanese people."
American troops working hand in hand with SDF personnel saved lives and provided critical supplies. Ten years later, Washington and Tokyo are confident that cooperation during the crisis deepened the decades-old alliance.
The cooperation that led to Operation Tomodachi was rooted in a relief mission by the U.S. in another disaster 16 years earlier -- the Kobe earthquake that struck western Japan in January 1995. Tokyo accepted an offer of assistance from Washington, which sent large quantities of blankets and drinking water and helped set up tents to provide shelter.
Even so, the U.S. was initially skeptical of Japan's commitment to contain the Fukushima disaster.
Washington's frustration toward Tokyo was made clear in a call by Michael Mullen, then the chairman of the U.S. Joint Chiefs of Staff, to senior SDF officials a few days after the Fukushima Daiichi accident. Katsutoshi Kawano, then vice chief of staff of Japan's Joint Staff, recalled that Mullen questioned what Japan was doing and said it was the SDF's job to put their lives at risk to handle a national crisis.
Then Kan issued the order. "That's when Operation Tomodachi began in earnest," Kawano recalled. American forces moved once Tokyo had taken action on its own initiative -- in keeping with the nature of the alliance itself.
At its peak, the operation mobilized 24,500 American personnel, 24 ships and 189 aircraft. U.S. forces distributed 280 tons of food and 7.7 million liters of water.
The alliance has grown stronger in the decade since. Some observers credit this to Japanese security legislation passed in 2015 that allows for limited exercise of the right to collective self-defense. The legislation also let the SDF provide armed protection for American ships and aircraft in peacetime, with a record 25 such operations conducted in 2020.
The two countries also have taken steps to heal the wounds left by World War II. In May 2016, Barack Obama became the first sitting U.S. president to visit Hiroshima. Later that year, then-Japanese Prime Minister Shinzo Abe traveled to Pearl Harbor.
Tokyo's role in defense cooperation has gradually widened under the Japan-U.S. security treaty, which had its 60th anniversary in June 2020.
A turning point came in 1991, amid the Persian Gulf War. After Japan faced international criticism for refusing to contribute personnel to the conflict, Tokyo dispatched ships to the gulf after the conflict for minesweeping operations, marking the SDF's first deployment abroad.
The joint Japan-U.S. declaration on security in 1996 broadened the scope of the alliance and emphasized its role in supporting "peace and security in the Asia-Pacific."
After the terrorist attacks in the U.S. on Sept. 11, 2001, the SDF began operating overseas on a regular basis in the Indian Ocean and Iraq. More recently, defense cooperation between Washington and Japan has expanded to cover space and cybersecurity.
China's growing military capabilities present one of the main challenges faced by the two countries. Secretary of State Antony Blinken and Defense Secretary Lloyd Austin are expected to discuss this issue when they visit Japan next week for a "two-plus-two" dialogue with counterparts Toshimitsu Motegi and Nobuo Kishi.
The choice of Japan for the first foreign trip by both Blinken and Austin signals the importance of the alliance to Washington. The dialogue will let the two sides discuss the division of labor within the alliance over the long term.
The administration of new President Joe Biden has little bandwidth to handle security issues as it grapples with the coronavirus pandemic and deep political rifts at home. His Democratic Party traditionally prefers to limit military spending, and some in Japan expect Washington to push Tokyo for more action to maintain the alliance's effectiveness as a deterrent.
Japanese lawmakers began debating last year whether to build capabilities for striking enemy missile bases in response to an imminent launch, after suspending plans to deploy the Aegis Ashore missile shield. The White House and Congress are weighing a missile network along the region's "first island chain," which encompasses Okinawa and the Philippines, with an eye toward China.
Japan may find itself with more defense responsibilities in the years to come.