Analysts point out that global allies' confidence in the US nuclear umbrella is rapidly eroding, as US President Donald Trump's latest "2026 National Defense Strategy" no longer explicitly mentions extended deterrence and urges allies to increase defense spending. This has prompted more countries to reconsider acquiring their own nuclear weapons, increasing the risk of nuclear proliferation. Ankit Panda, a senior fellow at the Carnegie Endowment for International Peace, stated that allies generally perceive Washington as becoming "more detached and unreliable."

Recent developments include:
Donald Trump ordered a reduction in joint military exercises with South Korea.
The US negotiated with South Korea on peaceful nuclear enrichment last month and signed a Saudi civilian nuclear agreement, which reportedly could create conditions for domestic nuclear enrichment in Saudi Arabia.
French President Macron announced in March this year that the country would increase its number of nuclear warheads for the first time since 1992, and pledged to extend its nuclear umbrella to nine other EU countries, including Germany and Greece, through "forward deterrence" partnerships.
Japanese Prime Minister Sanae Takaichi did not rule out revising Japan's three non-nuclear principles late last year, sparking speculation that it might abandon decades of non-nuclear commitment.
Leaders of Lithuania and Finland, which border Russia, are also inclined to abolish long-standing domestic bans on deploying nuclear weapons.

Analysts warn that while these developments do not yet constitute a decision to build nuclear bombs, a country's efforts to enhance its own security could make adversaries feel insecure, thereby encouraging pre-emptive action. A June report by the Stockholm International Peace Research Institute shows that the world's nine nuclear-weapon states (the United States, Russia, China, the United Kingdom, France, India, Pakistan, North Korea, and Israel) continue to modernize and expand their nuclear arsenals, exacerbating the arms race and bringing "new risks of miscalculation" amid escalating tensions. UN Secretary-General Guterres warned at a May meeting that the Nuclear Non-Proliferation Treaty is "eroding."