Texas Republican US Senate Primaries at a Glance

Through 2024, John Cornyn has drawn nearly half of all primary challengers to Texas GOP U.S. Senators in state history

With nearly a dozen U.S. Senators yet to announce their 2026 reelection plans, at the moment the highest profile primary races with incumbents on the ballot next year involve Republicans, notably Louisiana’s Bill Cassidy and Texas’ John Cornyn.

Cassidy’s opponents include sitting state Treasurer John Fleming while Cornyn also faces an elected statewide official – Attorney General Ken Paxton.

The Texas race is generating the most attention, in no small part because early polling shows Senator Cornyn already trailing Paxton in a head-to-head match up.

Whether or not Cornyn loses the March 3rd primary (or a potential May 26th runoff) next year, the contest is easily poised to be the toughest renomination battle any Republican U.S. Senator has faced at the ballot box in Texas history.

To date, Texas GOP U.S. Senators who have run for reelection have been renominated all 13 times: John Tower  (1966, 1972, 1978), Phil Gramm (1990, 1996), Kay Bailey Hutchison (1994, 2000, 2006), Cornyn (2008, 2014, 2020), and Ted Cruz (2018, 2024).

Incumbents received a free pass running unopposed in six of these cycles: Tower in 1966, 1972, and 1978, Gramm in 1990, and Hutchison in 2000 and 2006.

All told, only 26 challengers have squared off against Republican U.S. Senators during these 13 primaries held through 2024 – with 12 of those filing to take on Cornyn.

None of these 26 Republican challengers have received even 20 percent of the primary vote and only four have garnered double-digit support – though all four were opponents of Cornyn.

The high water mark is currently held by U.S. Representative Steve Stockman during his 2014 campaign.

Stockman won 19.1 percent in an eight-candidate field while losing to Cornyn by 40.3 points – both current all-time records for Republican Party challengers, and marks that Paxton should demolish next March. Stockman fell 9.5 points shy of dragging a Texas GOP U.S. Senator to a primary runoff for the first time in party history.

Also reaching double digits are telecommunications consultant Larry Kilgore in 2008 with 18.5 percent in a head-to-head primary matchup against Cornyn and oil field emissions businessman Dwayne Stovall with 10.7 and 12.0 percent en route to Cornyn winning his third and fourth terms in 2014 and 2020 respectively.

Overall, Texas Republican U.S. Senators have won their primaries by an average of 83.4 points (69.2 points in primaries with opposition).

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