The assessment is 'likely_true' based on strong, consistent evidence from multiple sources. Several high-authority sources, including the Wall Street Journal and MSN, explicitly confirm the existence of a Kalshi prediction market concerning a Supreme Court case on Donald Trump's tariffs. This establishes the fundamental context of the statement as factual. The specific figure of a '21% probability' is directly supported by a highly relevant, though low-authority, Instagram source. This source mentions a price of '21 cents' in the context of the tariff case. In prediction markets like Kalshi, a contract price of 21 cents is the direct representation of a 21% probability for the event to occur. While no other source corroborates this exact number, crucially, none of the sources contradict it. The high-authority sources confirm the market's existence, and the low-authority source provides the specific, uncontradicted data point. The convergence of evidence, with strong contextual support from credible outlets and a specific data point from another source, makes the original statement highly plausible.