Return of nuclear power politics: How great is the danger of a new arms race?

A growing number of nations are increasingly relying on nuclear deterrence, signaling a potential new arms race, warns the Stockholm International Peace Research Institute (SIPRI). All nine countries possessing nuclear weapons have reportedly modernized and expanded their arsenals during 2025, introducing not only new warheads but also advanced delivery systems.

These new systems, including missiles and cruise missiles, are designed to carry both conventional and nuclear payloads. SIPRI researchers highlight a general trend where more states are turning to nuclear weapons for national defense. Titi Erasto, a researcher at SIPRI, points to Finland and Sweden as examples of this shift. Historically neutral proponents of disarmament, these nations have drastically altered their nuclear policies following Russia's 2022 invasion of Ukraine and their subsequent accession to NATO.

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These countries, which were historically known as militarily neutral advocates for nuclear disarmament, are now actively participating in NATO's nuclear policy, for example, through participation in exercises simulating the use of nuclear weapons.

"These countries, which were historically known as militarily neutral advocates for nuclear disarmament, are now actively participating in NATO's nuclear policy, for example, through participation in exercises simulating the use of nuclear weapons," Erasto explained. While the total number of nuclear warheads globally saw a slight decrease in 2025, this is attributed to the decommissioning of older warheads rather than a reduction in overall nuclear capability. SIPRI anticipates this trend will reverse as the pace of dismantling slows while the deployment of new nuclear weapons accelerates.

The erosion of arms control agreements, such as the expiration of the New START treaty between the U.S. and Russia in February, further exacerbates the situation. "There are increasing signs that nuclear-weapon states are neglecting or even completely abandoning their disarmament obligations and instead demonstrating their nuclear power," noted Hans M. Kristensen, a nuclear weapons expert. This reliance on nuclear solutions, he warns, creates new risks and fuels an arms race dynamic.

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There are increasing signs that nuclear-weapon states are neglecting or even completely abandoning their disarmament obligations and instead demonstrating their nuclear power.