After START, need for new stabilising mechanisms

The Trump Administration’s decision to let the last remaining nuclear arms-control treaty with Russia lapse marks a historic inflection point in the management of dangerous weapons. Since the 1950s, the US viewed legally binding, treaty-based ceilings and intrusive verification as the core instruments for achieving global stability and mutual security among the great powers. Trump’s approach breaks sharply from that tradition. It emphasises unconstrained deterrence, unilateral technological advantage, and flexible force postures as better suited to American interests. This shift aligns with Washington’s broader reorientation under Trump on global economic and political institutions. In Trump’s view, classical arms control locked the US into outdated constraints while ignoring the real drivers of future instability: China’s rapid nuclear expansion, the proliferation of new delivery systems, and the rising prominence of tactical and theatre-level nuclear weapons.

The Strategic Arms Reduction Treaty (START) had capped US and Russian arsenals at 1,550 deployed strategic warheads and 700 deployed delivery systems, underpinned by rigorous data exchanges and inspections. With its demise, those limits and verification mechanisms have disappeared. For Russia, such treaties symbolised great-power parity with Washington; yet, the underlying asymmetry is stark. The US economy is nearly 12 times larger and enjoys a vast technological lead. The Trump Administration does seek stable relations with Moscow, but not through the late-20th-century template of codified equivalence. Analysts warn that the post-START environment will fuel hedging and worst-case planning, accelerating a renewed arms race. The risks are amplified by the rise of novel systems — hypersonic vehicles, dual-capable missiles, and exotic delivery platforms — that lay outside the treaty’s scope.

The collapse of formal arms control will create ripples well beyond US-Russia relations. States feeling vulnerable may sense fewer constraints on pursuing nuclear options. Efforts to bring China into future frameworks will not get far, because Beijing has no interest in freezing its arsenal at a position of inferiority. Europe, already unsettled by Russian aggression and uncertainty about US commitments, may drift towards strengthening a “Eurodeterrent,” alongside rising pressures on Japan and South Korea to consider their own nuclear capabilities. India, too, must confront the reality of emerging nuclear multipolarity. Rather than remain a bystander, Delhi must engage major powers in shaping new norms and stabilising mechanisms for a world with many nuclear actors.