Key Takeaways

  • A US withdrawal from NATO would be the largest strategic gift to Russia in modern history.
  • Europe would not collapse — but it would rearm rapidly and align away from Washington.
  • American security guarantees in Asia would also be questioned if NATO commitments prove unreliable.

AI Summary

Key takeaways highlight A US withdrawal from NATO would be the largest strategic gift to Russia in modern history. Europe would not collapse — but it would rearm rapidly and align away from Washington. American security guarantees in Asia would also be questioned if NATO commitments prove unreliable.

Foreign Policy

What Happens If the US Leaves NATO?

May 27, 2026 · 2 min read

The Trump administration keeps floating the idea of leaving NATO or reducing the US commitment to the point of meaninglessness. Let us think through what that actually looks like.

NATO's deterrence value comes almost entirely from two things: America's conventional military power, and America's nuclear umbrella. Remove both, and you have a military alliance with significant capability but no credible first-strike deterrent and no ability to rapidly reinforce Eastern Europe at scale.

For Russia, a NATO without the United States is a strategic dream that Vladimir Putin has spent 25 years working toward. The entire logic of Russia's pressure campaign against NATO — the provocations, the hybrid warfare, the election interference — is aimed at fracturing the alliance. Walking out would hand him the win without Russia firing a shot.

Europe's response would not be to fold. Germany has already announced the largest military buildup in its postwar history. France has accelerated discussions about extending its nuclear deterrence to other European members. The EU is developing a defense fund independent of NATO. (Financial Times, EU Defense Spending) Europe would rearm. It would just take a decade, and the gap in the meantime is dangerous.

The secondary consequence gets less attention: Asia. Japan, South Korea, and Taiwan look at American security guarantees and ask a simple question — if the US abandons treaty allies in Europe, why would it honor commitments in the Pacific? The answer gets harder to give every time another red line is crossed without consequence.

Alliances are credibility. When you stop showing up for allies in Europe, allies in Asia notice.

NATO is not perfect. The complaints about burden-sharing are not entirely wrong. But "they should spend more" is a negotiation. "We might leave" is a demolition.

The US built this system after World War II because unilateral power projection is expensive and exhausting. Destroying it in exchange for nothing is not America First. It is America Alone.

FAQ

What happens if the US leaves NATO?

A US withdrawal from NATO would remove the primary deterrent against Russian military aggression in Europe. European members would rapidly increase defense spending, develop independent nuclear deterrence options, and likely build a parallel security structure. American influence over European policy would collapse, and the geopolitical signal to China and North Korea about US commitment reliability would be severe.

Can the US legally leave NATO?

The NATO treaty does not include a withdrawal clause, but the US could give formal notice and withdraw unilaterally. Congress has passed legislation requiring congressional approval before a president can withdraw, though whether that is constitutionally binding is contested.

Would Europe be safe without the US in NATO?

Europe has significant military capability, but it is fragmented across national militaries with incompatible systems and no unified command. Without the US, NATO's nuclear deterrence would rest on French and British arsenals, which are much smaller. Europe would be less safe in the short term, though it would invest heavily to close the gap.

Has the US ever threatened to leave NATO before?

Threats to reduce NATO commitment were made during Trump's first term but never formalized. What is different in 2026 is the broader pattern of withdrawal from international institutions — over 60 organizations — which makes the threat more credible to European governments than it was before.

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