Japan and the United States held their first ministerial meeting on extended deterrence to underline the robustness of the U.S. nuclear umbrella amid growing security challenges from China, North Korea and Russia.

“By holding discussions centered on extended deterrence, we can expect a further synergistic effect toward strengthening the deterrence of the Japan-U.S. alliance,” Defense Minister Minoru Kihara told the meeting in Tokyo on July 28.

U.S. Secretary of Defense Lloyd Austin also said the bilateral relationship of extended deterrence is more important than ever. He said China, Russia and North Korea are threatening global security by focusing on nuclear capabilities.

The meeting was also attended by Foreign Minister Yoko Kamikawa and U.S. Secretary of State Antony Blinken.

The joint statement noted “an increasingly deteriorating regional security environment,” citing North Korea’s development of nuclear weapons and missiles to deliver them, the expansion of China’s nuclear arsenal and Moscow’s military cooperation with Pyongyang.

“Under these circumstances, the United States and Japan reiterated the need to reinforce the alliance’s deterrence posture, and manage existing and emerging strategic threats through deterrence, arms control, risk reduction, and nonproliferation,” the statement said.

Extended deterrence refers to discouraging an enemy from attacking an ally by demonstrating a willingness to retaliate with nuclear or conventional weapons.

Japan and the United States have held an extended deterrence dialogue, or EDD, between working-level foreign and defense officials once or twice a year since 2010, a year after Barack Obama became U.S. president.

Japan feared that the goal of a “world without nuclear weapons,” advocated by the Obama administration, could undermine the U.S. nuclear umbrella extended to its allies.

In 2009, Takeo Akiba, then Japan’s minister to the United States, told the U.S. side that a unilateral reduction in U.S. strategic nuclear warheads could have an adverse impact on Japan’s national security.

Tokyo called on Washington to start the EDD framework as a forum where the two countries would share the importance of the nuclear umbrella.

The United States has used EDD sessions to reassure Japan. U.S. officials have shown their Japanese counterparts nuclear-capable strategic bombers, a launch control center for intercontinental ballistic missiles and other equipment and facilities in the United States.

However, a further deterioration in Japan’s security environment in recent years prompted Tokyo to ask Washington to upgrade the EDD to a ministerial level, according to Japanese government sources.

Moscow, Beijing and Pyongyang have all caused increased concern about nuclear war through a range of words and actions.

Russia has warned of using nuclear weapons on several occasions since it launched a full-scale invasion of Ukraine. China is rapidly enhancing its nuclear capabilities.

And North Korea has accelerated its nuclear and missile development and also deepened military cooperation with Russia.

The United States has also faced the need to demonstrate to the Japanese side that its nuclear and other deterrence capabilities are credible.

After their summit in April, Prime Minister Fumio Kishida and U.S. President Joe Biden said in a joint statement: “We reaffirm the critical importance of continuing to enhance U.S. extended deterrence, bolstered by Japan’s defense capabilities, and will further strengthen bilateral cooperation.

“In this regard, we call on our respective foreign and defense ministers to hold in-depth discussions on extended deterrence on the occasion of the next security (consultative committee) ‘2+2’ meeting.”

A senior Defense Ministry official welcomed the first ministerial meeting on extended deterrence.

“It is a big step forward that Japanese and U.S. ministers can now discuss extended deterrence,” the official said.

A senior U.S. Defense Department official also indicated that the holding of a ministerial meeting itself will serve to demonstrate that the U.S. nuclear umbrella is secure.

Critics say nuclear deterrence has the disadvantage of creating a cycle of mutual distrust and militarization.

Kishida has emphasized that Japan should strive for the goal of a world without nuclear weapons, referring to its unique position in history as the only country to have experienced atomic bombings.

And yet the ministerial meeting on extended deterrence was designed to show that Japan is being protected by the U.S. nuclear umbrella, a contradiction of Kishida’s position.

In fact, Kishida has never questioned Japan’s dependence on U.S. nuclear weapons, nor has a range of previous governments.

Japan has not joined the Treaty on the Prohibition of Nuclear Weapons, which has been signed by more than 90 countries.

And nor has Kishida sent an observer to a meeting of state parties to the treaty, unlike Germany, another country under the U.S. nuclear umbrella.