Will US withdraw from NATO by 2027?

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Active sub-markets

Market context

The real-world event at the core of this market is whether the United States formally submits a notice of denunciation to withdraw from NATO under Article 13 of the North Atlantic Treaty before the end of 2026. This action requires only a one-year waiting period after the notice is given to the US Government, which then informs other allies, but it is legally constrained by the 2024 National Defense Authorization Act, which mandates congressional approval for any unilateral withdrawal[2][5].

Historically, no member has ever invoked Article 13 to leave NATO, and the 1951 Greenland agreement implies that continued NATO participation is essential for US access rights, making withdrawal a high-stakes geopolitical shift rather than a routine procedural step[1]. While President Trump has threatened withdrawal, the legal barrier requiring a two-thirds Senate majority or congressional act significantly lowers the probability of a formal notice being issued, aligning with the current 5% crowd-implied probability[2][3].

Traders should monitor scheduled congressional hearings on defence policy and any public statements from the White House regarding NATO commitments, as these serve as primary catalysts for potential withdrawal moves. Recent reporting confirms that the NDAA for Fiscal Year 2024 explicitly prohibits the President from withdrawing without congressional authorization, meaning any shift in probability would likely stem from a change in legislative stance rather than executive action alone[2][5]. Programmatically, this market is best approached by setting conditional orders that trigger only if a notice of denunciation is officially filed with the US Government, as the settlement criteria are binary and time-bound[2].

Sources: 1 · 2 · 3 · 4 · 5

Methodology

Methodologically we separate two layers: the live probability (Polymarket mid-price) and the platform attributes (fee, KYC, settlement currency, payment rails). The odds column is filled only where we have clean data — that avoids the made-up numbers that get a network demoted when search engines cross-check against the source venue.

Resolution & payout

Polymarket-based markets settle through the UMA Optimistic Oracle on Polygon. A proposer submits the outcome, a two-hour challenge window opens, and unchallenged proposals finalise the resolution. Payouts settle automatically in USDC the moment the result is final — no bookmaker, no delay.

Kalshi-based markets settle in USD via the CFTC-regulated clearinghouse. Betfair Exchange settles in GBP/EUR net of commission. Manifold is play-money and does not pay out real funds.

FAQ

How does resolution work?

Through the UMA Optimistic Oracle on Polygon: a proposer submits the outcome, a two-hour challenge window opens, and USDC payouts settle automatically once the result is final.

What's the difference between YES and NO shares?

A YES share pays $1.00 if the event happens, $0 otherwise. A NO share pays $1.00 if the event doesn't happen. The market price between 0¢ and 100¢ is the implied probability.

What does it cost to trade on Polymarket Review UK?

Zero. Polymarket Review UK routes every order to the live Polymarket order book; the only cost is the Polygon network fee, typically under $0.01 per transaction.

How fast are USDC deposits?

Polygon credits deposits after 12 confirmations — usually under 30 seconds. Withdrawals follow the same path and land back in your wallet within minutes.

How reliable are the quoted odds?

The YES/NO percentages are the live mid-prices of the Polymarket order book. On deep markets they move every few seconds; on thinner ones you'll see short plateaus.