Seventy-four years ago this week, two U.S. atomic bombs were dropped on Hiroshima and Nagasaki, taking the lives of roughly 200,000 people almost instantly in what were the first and so far only nuclear attacks in history. Days later Japan surrendered, ending World War II. The annual memorial for the atomic bombing victims held by the city of Hiroshima on Tuesday was the first to be held in the new imperial era of Reiwa.

The transition from Showa to Heisei to Reiwa testifies to the decades that have passed since the atomic bombings, and the number of people with firsthand experience of the 1945 atomic bombings is steadily falling. The people who survived the horrific bombings are growing old — 82.65 years old on average — and the number of survivors is declining by more than 9,000 each year. As of the end of March, the number of hibakusha stood at 145,844.

But even after the passage of nearly three-quarters of a century, the world remains no closer to the elimination of nuclear weapons, which has been the stated goal of Japan as the sole country to have experienced nuclear attacks. Even worse, recent developments surrounding nuclear arms threaten to shake the taboo against using them due to their grave humanitarian consequences.

The Intermediate-Range Nuclear Forces Treaty, which was introduced by the United States and the Soviet Union in 1988 and was the centerpiece of the post-Cold War nuclear arms reduction efforts, expired last week when the U.S. officially withdrew from it. Amid deteriorating relations between the U.S. and Russia — which possess some 4,000 operable nuclear warheads each — Washington had accused Moscow of violating the terms of the treaty by developing a new land-based, nuclear-capable cruise missile. The U.S. administration of President Donald Trump — also frustrated by the exclusion of China from the INF treaty — cited its charge of noncompliance by Russia as grounds for its pullout from the agreement.

The demise of the treaty threatens to unleash a new arms race. Russia has denied the U.S. charges but says it will match any new U.S. missile deployments. Meanwhile, China, whose nuclear arsenal is smaller than those of the U.S. or Russia, is steadily building up its nuclear capabilities both quantitatively and qualitatively. Termination of the INF treaty also clouds prospects for the New START (Strategic Arms Reduction Treaty), which is set to expire in 2021. Although it can be extended for another five years, there is little indication that negotiations between the U.S. and Russia for renewing the treaty are making any progress.

Concern lingers over the proliferation of nuclear weapons. Despite the three rounds of summit talks between the U.S. and North Korea that have been held since last year, expectations for ending Pyongyang’s nuclear weapons and ballistic missile programs — which pose a serious threat to the security of Japan — remain low as concrete steps are yet to be taken for the “denuclearization” of Kim Jong Un’s regime. The U.S. withdrawal from the multinational agreement to cap Iran’s nuclear program has put the 2015 deal in limbo and ratcheted up tensions in the Persian Gulf.

As things stand, there seems to be little room for Japan, which continues to rely on the nuclear umbrella of the United States for its own security, to play a meaningful role in the push for nuclear disarmament. During the memorial in Hiroshima on Tuesday, Mayor Kazumi Matsui called on the government to exert more leadership to eliminate nuclear arms as the sole country to have suffered nuclear attacks, and specifically to sign and ratify a nuclear weapons prohibition treaty, which was adopted in July 2017 by more than 120 countries at the United Nations but has yet to take effect since not enough signatories have ratified it.

Along with the nuclear weapons powers and other countries reliant on the nuclear umbrellas of their allies, Japan refused to become a signatory of the treaty to ban the acquisition, development, production, manufacture, possession, transfer, receipt, testing, extraterritorial stationing, use and threat of use of nuclear weapons.

Prime Minister Shinzo Abe, who attended the Hiroshima memorial, called it Japan’s mission to make strenuous efforts to realize “a world free of nuclear weapons” by serving as a bridge to promote dialogue between nuclear powers and non-nuclear states, without referring to the nuclear ban treaty. In a news conference later, Abe reiterated his government’s opposition to the treaty, which he said does not reflect the true national security perspective due to the nonparticipation of the nuclear weapons powers.

Japan, then, will be pressed to show what concrete actions it intends to take to play a more proactive role to achieve a world free of nuclear weapons.