**Senator John Fetterman’s low implied probability of vacating his Pennsylvania Senate seat by late 2026 stems from his repeated public denials of any intent to resign or switch parties, combined with structural factors favoring continuity.** His six-year term runs through January 2029, and a Democratic governor would appoint any replacement. Recent catalysts include a September 2026 Wall Street Journal report detailing alleged disengagement from constituent meetings and hearings, which prompted some Democratic calls for resignation, and his surprise video appearance at a Republican midterm convention that briefly lifted party-switch speculation. Fetterman has pushed back forcefully, stating he remains a Democrat focused on issues like Israel policy and border security while rejecting GOP affiliation. No official resignation signals or health developments have emerged in the past month, and traders appear to price the outcome as tail-risk rather than base-case given his leverage ahead of the November midterms and lack of immediate pressure to exit.