Will US withdraw from NATO by 2027?

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Active sub-markets

Market context

The United States formally initiating withdrawal from NATO by notifying the alliance under Article 13 of the North Atlantic Treaty is the real-world event this market tracks. Despite recent legislative pushes by Republican lawmakers like Senator Mike Lee and Representative Thomas Massie to force such a notice, the crowd-implied probability of 5% reflects the substantial legal and political hurdles, including a 2023 law requiring a two-thirds Senate majority for exit[5].

Historically, no NATO member has ever exited the 77-year-old alliance, and the withdrawal procedure itself is straightforward but politically constrained, requiring only one year’s notice yet demanding congressional authorization to bypass unilateral presidential action[3][5]. The 5% probability aligns with this precedent, as even if a bill like the NATO Act passes, it faces intense scrutiny and likely judicial or legislative blocking before a formal notice could be issued[2][6].

Traders should monitor upcoming congressional votes on withdrawal bills, statements from the Trump administration regarding NATO commitments, and any shifts in Senate leadership that could alter the two-thirds threshold[5]. Recent news confirms Massie’s bill explicitly prohibits US funding for NATO’s common budgets, a move that could galvanise opposition but also signal growing isolationist sentiment[4]. On Polymarket, decimal odds may show 19.00 for “No”, while Kalshi’s implied probability of 5% and stricter KYC requirements create divergent liquidity profiles compared to Betfair’s open-access model.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page compares Will US withdraw from NATO by 2027? specifically across Polymarket, Kalshi, Betfair Exchange and Smarkets. Live odds come from the Polymarket order book; the other venues' contract details are maintained manually because their APIs aren't directly comparable. Every CTA routes to PolyGram, which mirrors the Polymarket order book at 0% fees.

Resolution & payout

Settlement is the biggest difference between the four platforms: Polymarket on-chain in USDC (instant), Kalshi USD via CFTC (T+1), Betfair and Smarkets in local currency via bank withdrawal (T+1 to T+3). PolyGram routes every trade directly into Polymarket's on-chain settlement, which is why payouts land fastest.

FAQ

Where can I trade this market with the lowest fees?

On PolyGram, which mirrors the Polymarket order book at 0% fees. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

Is this market available outside the US?

PolyGram is available in most jurisdictions where Polymarket isn't directly accessible. Polymarket itself is geo-blocked in the US/UK/EU. Always check local regulations.

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.

Do I need to KYC for this market?

Not under $1,500 of lifetime trading volume. Above that threshold, PolyGram triggers a quick verification flow that finishes in 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.