Europe, Canada, Japan and South Korea are discussing an alternative to the “American nuclear umbrella”

Canadians are openly debating the merits and risks of pursuing a nuclear weapon, and likewise, Europeans are considering creating a nuclear deterrent for the Union.

In South Korea, public support for a nuclear weapon is at an all-time high, and even in Japan some politicians are talking about this once taboo topic.

Just a few years ago, few experts would have predicted that these countries, all allies of Washington, might one day join the nuclear club.

Since 2006, this club has consisted of only nine countries: the United States, Russia, the United Kingdom, France, China, India, Pakistan, North Korea, and Israel, with its undeclared program.

Nonproliferation advocates had hoped that nine would be the maximum, but over the past years, more countries have begun to seriously explore “joining the nuclear club.”

Perceived national security threats continue to shape U.S. allies’ views on nuclear weapons development, with North Korea a major driver for South Korea and China a critical factor for Japan.

But what has clearly changed for many of the United States’ allies is the doubt that has begun to emerge, recently, about the credibility of the so-called “American nuclear umbrella,” which has provided allies, for decades, an easy way to reject the pursuit of possessing nuclear weapons.

Because of their concern about the foreign policy of the administration of US President Donald Trump, some countries are considering developing domestic nuclear weapons programs or seeking new deterrence guarantees.

Tacit understanding

The United States dropped the first two atomic bombs on Japan in 1945, and the former Soviet Union conducted its successful nuclear test four years later. The United Kingdom was next to obtain the bomb in 1952, followed by France in 1960, and China in 1964.

Experts believe that Israel conducted its first bomb test in the late 1960s, while the last countries to join the nuclear club were India in 1972, Pakistan in 1998, and North Korea in 2006.

Experts have long wondered which country might be next, and speculation has mostly included US allies such as Japan, South Korea and Turkey.

For many years, it was assumed that these countries fell under the US nuclear umbrella, an implicit understanding that Washington would defend its non-nuclear allies, including by using US nuclear weapons.

Doubts about the credibility of the US nuclear umbrella have been around for years, and they predate the Trump administration.

Other options

However, current US officials’ criticism of NATO, their focus on burden-sharing, and their policy positions toward Ukraine have clearly highlighted to allies the need to consider other nuclear options.

With allies now focused on the limits of American security guarantees, the list of countries that might aspire to acquire nuclear weapons has suddenly grown.

European leaders have carefully crafted their public comments on the issue, focusing on concerns about overall US reliability versus the credibility of the US nuclear umbrella.

Perhaps the Chairman of the Defense Committee in the Danish Parliament, Rasmus Jarlov, best expressed the views of many of the United States’ allies in Europe, as he told the Associated Press: “If things get really dangerous, I very much doubt that Trump will risk American cities to protect European cities,” adding: “We do not know, but it seems that relying on American protection is risky.”

Joint deterrence

Most public discussions in Europe focused on the concept of the bloc’s joint nuclear deterrent under the protection of French nuclear forces. In an important speech he delivered recently, French President Emmanuel Macron called for “forward deterrence,” which involves the temporary deployment of French nuclear-armed aircraft in nine other European countries, including Germany and Poland.

Meanwhile, Swedish Prime Minister Ulf Kristersson held talks with Britain and France about deploying the two countries’ nuclear forces in Sweden in times of war. But the French pledge does not include a guarantee that the allies will be defended using French nuclear weapons. Instead, France will use nuclear deterrence to defend French “vital interests,” an intentionally vague phrase.

Only time will tell whether Macron’s offer will satisfy European partners, or prevent them from deciding to take matters into their own hands.

Speculation has been growing about whether Poland and Germany are considering developing their own nuclear weapons, and while German Chancellor Friedrich Merz has explicitly ruled this out, comments from Polish leaders leave the option open.

In early March, Polish Prime Minister Donald Tusk told the Polish Parliament that his country “must seek the latest solutions related to nuclear weapons,” in statements that seemed to reflect his personal support for Warsaw’s long-term quest to possess a nuclear weapon, and the ongoing talks in the near term with the French side regarding the nuclear umbrella.

Canada and Japan

In Canada, military officials said last month that Canada should not rule out possessing nuclear weapons. Although these statements were met with opposition from Canadian Defense Minister David McGinty, the debate over whether Canada would consider “going nuclear” was not out of context in the current global security environment, and similar discussions are echoed among current and former government officials across Asia.

For Japan, these talks represent an important development. Article 9 of the Japanese Constitution, largely drafted by the “American occupation authorities” after World War II, stipulates the renunciation of war.

In 1967, Japan also pledged not to produce, possess, or host nuclear weapons on its territory, the “Three Principles of Non-Nuclear Capability.”

The issue of possessing nuclear weapons is no longer taboo in Japan. In late 2025, an unnamed official in the new administration of Prime Minister Sanae Takaichi expressed his personal opinion that Japan should begin discussions on developing these weapons. These statements sparked an official rebuke from Takaichi. Moreover, Japanese nuclear weapons are unlikely to be on the agenda anytime soon, especially given the sensitivity surrounding Japan’s status, as the only country to have directly suffered the consequences of nuclear weapons. However, the ruling Liberal Democratic Party, led by Takaichi, is reconsidering its position on Tokyo’s non-nuclear principles, to discuss allowing US nuclear weapons into Japanese territory. About “The Conversation”

South Korea’s position

South Korean Foreign Minister Park Jin, under the administration of former conservative President Yeon Suk-yeol, said that Seoul’s independent nuclear deterrent “has not been ruled out,” given the unpredictability of the actions of the administration of US President Donald Trump. This was not mentioned explicitly, but it was clear in the background, as there were concerns about the American nuclear umbrella.

South Korea’s former nuclear weapons program, coupled with popular support for its revival, may already make it possible for Seoul to acquire a nuclear weapon in the future, although the current center-left government emphasizes Seoul’s anti-nuclear stance.

• Countries are considering developing nuclear weapons or seeking new deterrence guarantees because of their concern about Trump’s policy.

• Most public discussions in Europe focused on the concept of joint nuclear deterrence.