Chris Pappas holds an 88.5% implied probability in the New Hampshire Senate race because recent polling averages show him leading Republican John E. Sununu by 5–7 points among likely voters, with the Democrat at 48–51% and the Republican at 41–45% in surveys from late September through early October 2026. The open seat created by retiring Democratic Sen. Jeanne Shaheen’s decision not to run has produced a contest where Pappas, the four-term U.S. Representative who won his primary decisively, benefits from consistent advantages on economic and healthcare messaging in a state that has trended Democratic in recent Senate contests. Sununu, the former senator who secured the GOP nomination, has faced challenges closing the gap despite substantial outside spending and family name recognition, even as the candidates clashed over presidential leadership and affordability issues in their October 13 debate. Forecasters rate the race Lean or Likely Democratic, aligning with the market pricing ahead of the November 3 election.