The Most Expensive Primaries in U.S. History Had One Thing in Common

One Man, Two Primaries: Trump's Hand in the Massie and Paxton Fights

If you strip away all the noise about donors and lobbyists, both the Thomas Massie and Ken Paxton primaries come down to one man: Donald Trump. In Kentucky, Trump's endorsement helped end Massie's career; in Texas, his endorsement resurrected Paxton's and crushed a four‑term senator who outspent him by tens of millions of dollars.

Trump vs. Massie: When AIPAC Money Finally Worked

Thomas Massie wasn't just a critic of foreign aid to Israel — he was also one of the loudest Republican skeptics of Trump inside Congress. That made him a long‑term target for pro‑Israel groups and for Trump himself.

Pro‑Israel groups had already tried to knock Massie off before and failed. In 2020, the Republican Jewish Coalition backed a primary challenger against Massie and later walked it back. Then in 2024, AIPAC's United Democracy Project spent roughly $300,000 on ads portraying him as hostile to Israel — and Massie still won re‑election without breaking a sweat.

Those earlier efforts proved that AIPAC money alone couldn't take him out. What changed in 2026 was that Trump joined the pile‑on and endorsed his challenger Ed Gallrein — and that is when the floodgates opened.

Here are the receipts from the 2026 Massie primary:

• Total ad spending topped $32 million, making it the most expensive House primary in U.S. history, according to AdImpact.

• Over $25.8 million of that total came from outside super PACs — not the candidates themselves.

• AIPAC's electoral arm, the United Democracy Project, spent over $4.1 million. The Republican Jewish Coalition's RJC Victory Fund spent approximately $3.9 million. Together, those two pro‑Israel PACs alone put in over $8 million.

• Three PACs tied to pro‑Israel donors combined spent over $15.5 million in the race, according to FEC data.

• The MAGA KY super PAC, led by two senior Trump advisors and bankrolled in part by pro‑Israel billionaires Paul Singer and John Paulson, spent another $7.5 million supporting Gallrein.

• Gallrein won with approximately 55 percent of the vote.

To put that in perspective: AIPAC spent $300,000 against Massie in 2024 and lost. In 2026, with Trump endorsing their challenger, pro‑Israel groups came back with over $15 million — and this time Massie fell. The money didn't change. What changed was Trump.

Trump and Paxton: Winning While Being Outspent by About $80 Million

Ken Paxton's story is the exact opposite of Massie's. Instead of crossing Trump, he built his entire political identity around loyalty to Trump. When he challenged four‑term Senator John Cornyn in the Texas Republican Senate primary runoff, he ran as Trump's warrior against the old‑guard GOP establishment.

On paper, Paxton should have been completely buried by money. Here are the receipts from the 2026 Paxton primary:

• Total spending across the full Republican primary reached approximately $128 million, making it the most expensive Senate primary in U.S. history, according to AdImpact.

• Cornyn's campaign and his allied super PAC spent over $21 million in ads alone during the runoff period after the March primary.

• Paxton and his supporting super PAC spent only about $7 million in that same stretch.

• Overall, pro‑Cornyn groups outspent Paxton by approximately $80 million across the full race.

• Paxton still won the runoff by more than 25 points.

Despite being outgunned by roughly $80 million, Trump's late endorsement — which came just before the runoff — completely flipped the race. Cornyn had led in the earlier primary rounds. But once Trump put his name behind Paxton, Republican voters followed Trump and not the money.

The Common Thread: Trump Overrules the Money

Put both races side by side and one story emerges loud and clear.

In Kentucky, AIPAC and pro‑Israel donors tried and failed to beat Massie in 2024 with $300,000. In 2026, they came back with over $15 million in pro‑Israel PAC money — but it only worked because Trump endorsed their challenger at the same time.

In Texas, the GOP establishment and Cornyn's allies spent roughly $80 million more than Paxton had — and still lost, because Trump endorsed Paxton.

None of this proves anyone broke the law or that a single donor literally bought a seat. What it shows is how legal money and Trump's endorsement work together to decide which Republicans survive and which ones don't. AIPAC couldn't beat Massie alone. Cornyn's donors couldn't beat Trump alone. The real power in today's Republican primary is whoever has Trump's name behind them — and the receipts prove it.

If you are a voter, the real question is not just who is on the ballot — but which billionaire, which lobby, and which former president decided they were allowed to be there in the first place.