Prediction Markets Signal Declining Confidence in Supreme Court Ruling on Trump Tariffs

Prediction Markets Signal Weakening Confidence in Trump's Tariff Powers

Prediction markets are signaling declining confidence that the US Supreme Court will rule in favor of President Donald Trump’s sweeping tariff powers. Traders on regulated and crypto-native platforms have reduced their exposure following the week’s developments.

US-regulated event-market platform Kalshi showed Thursday that traders now assign a 29% chance that the Supreme Court will side with Trump, a 28-point drop in a single day. On Polymarket, Kalshi’s onchain competitor, where contracts are settled in USDC (USDC), the odds fell to 25%, reflecting a similar collapse in sentiment.

The combined trading volume across both platforms surpassed $1.3 million, demonstrating that traders participating in prediction markets can provide early indicators of sentiment linked to political and judicial outcomes. Traders are increasingly expecting the court to limit Trump’s authority to impose tariffs.

Assessing Political Risk Through Liquidity and Probability

Both markets have experienced volatility since the Supreme Court agreed to hear the case in September. However, Wednesday saw the largest single-day decline since the market went live.

This price swing suggests that traders are increasingly expecting the Supreme Court to limit the scope of presidential authority to impose tariffs under the emergency-powers law. This decision could significantly reshape how US presidents approach fiscal leverage and trade policy.

The alignment between Kalshi and Polymarket odds highlights a growing convergence between traditional and decentralized forecasting markets, where fiat-based and blockchain-based traders interpret political risks through similar lenses of liquidity and probability.

Supreme Court Justices Question Trump’s Tariff Powers

The sell-offs followed reports that several conservative justices appeared skeptical of Trump’s claim to unilaterally impose broad import duties using emergency powers.

On Wednesday, the Supreme Court held hours of oral arguments on one of the most consequential cases of the presidential term. The case challenges whether the president can rely on a 1977 emergency law to impose tariffs without the approval of Congress.

An Associated Press report noted that even among Trump-appointed justices, concerns surfaced about the separation of powers and the risk of concentrating fiscal authority in the executive branch.

Chief Justice John Roberts, Justice Neil Gorsuch and Justice Amy Coney Barrett reportedly pressed the US government on whether the 1977 International Emergency Economic Powers Act grants such an expansive authority. Barrett questioned why countries like Spain and France needed to be targeted, while Roberts emphasized that tariffs, as taxes, have always been the core power of Congress. Meanwhile, Gorsuch warned that allowing the executive branch such leeway could create a “one-way ratchet” toward unchecked presidential power.

Impact of Trump's Trade Policies on Crypto Markets

Trump’s trade policies have historically influenced crypto markets. Earlier tariffs fueled inflation fears and prompted traders to treat Bitcoin (BTC) as a hedge against fiscal instability. But at times, tariff-driven uncertainty also triggered risk-off sentiment, leading to short-term sell-offs as investors rotated into safer assets.