Incumbent Republican Ronny Jackson faces Democrat Mark Nair in the November 2026 general election for Texas's 13th congressional district, a Panhandle seat with an R+24 partisan lean. Jackson's March primary victory and substantial fundraising lead have reinforced trader expectations for a Republican margin clustered in the 30-45% range, where market shares concentrate. The absence of major campaign events, polling shifts, or national headwinds in recent weeks has kept probabilities distributed across those buckets rather than consolidating. A late surge in Democratic turnout, unexpected national conditions favoring the opposition, or significant candidate developments could narrow or widen the margin and shift shares among the listed Republican outcome ranges.