This market will resolve to “Yes” if the United States formally commits to giving Ukraine a security guarantee, defined as a publicly announced and mutually agreed deal between the Trump administration and the Government of Ukraine which creates a binding obligation for the United States to defend or directly intervene on Ukraine’s behalf, by December 31, 2025, 11:59 PM ET. Otherwise, this market will resolve to “No.” A qualifying “security guarantee” requires language that is equivalent in character to a NATO Article 5–style mutual defense commitment: the United States must commit to responding militarily if Ukraine is attacked, or otherwise guarantee Ukraine’s defense through binding defense obligations. Examples of qualifying language include commitments modeled on the US treaties with Japan, South Korea, or the Philippines, or NATO's Article 5 instrument, which obligates the United States to “act to meet the common danger” through military force if an ally is attacked. Cooperative frameworks, capacity-building measures, consultative mechanisms, or nonbinding pledges will not qualify. Examples of non-qualifying arrangements include the June 13, 2024 US–Ukraine bilateral security agreement, the Taiwan Relations Act, or G7/EU “security arrangements” that provide support or consultation but stop short of binding defense guarantees. A qualifying agreement must be jointly announced and finalized, and take the form of a treaty, executive agreement, memorandum of understanding, joint declaration, or equivalent written instrument. Announcements which are statements of intent, contingent, exploratory, or otherwise not indicative of a formalized policy will not count. The primary resolution source will be a consensus of credible reporting.