**NATO Article 5 requires an armed attack on a member state's territory and unanimous consensus among all 32 allies to trigger collective defense obligations.** Russia has conducted repeated hybrid actions, including drone incursions into Polish airspace and fighter jet violations over Estonia, prompting Article 4 consultations but not crossing the Article 5 threshold. These incidents, along with sabotage and cyberattacks, remain below the level allies treat as triggering mutual defense, consistent with assessments that Moscow is testing limits without seeking direct confrontation before 2027. NATO summits have reaffirmed the collective defense commitment while European members increase defense spending and readiness, and U.S. policy emphasizes burden-sharing. With only months remaining until 2027 and no unambiguous armed attack on alliance territory, traders price the probability of invocation accordingly low.