Massie’s primary is the most expensive in history. Pro-Israel groups have played a huge part.

The pro-Israel lobby that’s pumped millions into Democratic primaries this year is facing the next test of its political power on the right in ruby-red Kentucky.

The American Israel Public Affairs Committee and other pro-Israel interest groups have uncorked over $9 million in a bid to unseat Republican Rep. Thomas Massie on Tuesday in a competitive primary that has shattered spending records. Prominent pro-Israel GOP donors have funneled millions more into a super PAC stood up by President Donald Trump’s political operation that has spent nearly $7 million on the race. Overall ad spending has topped $32 million, making it the most expensive House primary on record, per tracking firm AdImpact.

Pro-Israel groups got the opening they needed to spend big against the isolationist lawmaker whenTrump decided to front a primary challenger to Massie, presenting the first serious threat to his reelection in over a decade. The Republican Jewish Coalition Victory Fund and United Democracy Project, AIPAC’s super PAC, have attacked the incumbent for his votes against symbolic measures supporting Israel.

And unlike in recent Democratic primaries where United Democracy Project has used shell PACs to shield its involvement, the powerful pro-Israel group’s political arm is investing directly in taking Massie out.

“He’s the most anti-Israel Republican in the House,” United Democracy Project spokesperson Patrick Dorton said of Massie. “This is a competitive, close primary situation. It’s always hard to defeat incumbents. … But we think there’s an opportunity here.”

Tuesday’s primary will serve as a key test of the lobby’s power over a party whose historically ironclad support for Israel is starting to show cracks in the wake of wars in Gaza and Iran. Unfavorable views of the U.S. ally are on the rise in the GOP, driven by slumping support among younger Republicans. Jewish Republicans are grappling over how to confront antisemitism in the party. And some prominent conservatives — including key Massie allies like Tucker Carlson and former Rep. Marjorie Taylor Greene (R-Ga.), who have also fallen out of favor with Trump — are amplifying views that are harshly critical of Israel in the name of adhering to “America First.”

Massie insists he is “not antisemitic” and “not against Israel.” In an interview Friday, he warned against “trying to equate criticism of the policies of Benjamin Netanyahu with antisemitism.”

Still, Massie is centering the crush of cash from pro-Israel groups and donors in his campaign, which he has acknowleged is his toughest reelection fight yet given Trump’s involvement and the outside spending it’s unleashed. Massie has accused his opponents of trying to buy his seat by boosting his Trump-backed rival, former Navy SEAL Ed Gallrein. On Thursday, he announced a bill that attempts to force AIPAC to register under the Foreign Agents Registration Act — a notable escalation in the closing days of the campaign.

“When this race is over, whether I won or lost, that’s the story: Were they able to come in and take out a Republican who’s skeptical of Benjamin Netanyahu’s policies?” Massie told POLITICO last month after a candidate forum in his district. “My opponent wouldn’t even be out of the starting blocks if it weren’t for that money.”

Republicans who strongly back Israel and its policies say defeating Massie is a step toward reasserting that supporting Israel is good politics — and a way to ward off candidates who hold critical views of the country in other races.

“For those of us who care about these issues, ousting Massie is critical,” said Gabe Groisman, a former Republican Jewish Coalition board member and Florida-based donor who is not involved in the race. “It’s super important to build and keep a wall, and let those [Israel-critical] voices remain outside voices and not inside voices on the floor making policy and impacting policy in Washington.”

Added one operative involved in the outside effort to oust Massie: "Other ambitious politicians might look at this race and think 'gee, that’s a pretty risky approach, maybe lining up with Tucker and Massie isn’t actually great politics.' Sane incumbents try to avoid primaries, and incumbents who follow Tucker off the cliff are going to get them.”

A libertarian-leaning conservative whose stands often make him a lone wolf in Congress, Massie has long drawn ire from Israel allies over his opposition to military aid to Israel and to symbolic resolutions supporting the country and condemning antisemitism. A spending hawk and frequent critic of foreign interventions who regularly is the sole vote against symbolic resolutions, Massie has said that he’s against all foreign aid, not just to Israel. He dismissed the resolutions as “meaningless” measures that he felt violated the First Amendment or had language equating anti-Zionism with antisemitism.

“Does Israel have the right to exist? Every country has a right to exist,” Massie said in his interview last month with POLITICO. He added: “Why do you need 30 resolutions on the floor of the House to support Israel?”

Massie has also criticized what he believes is AIPAC’s outsized influence in U.S. foreign policy. He has accused the bipartisan group, which has bundled millions of dollars for lawmakers on both sides of the aisle over the years, of leveraging its financial resources to keep congressional Republicans in line on Israel. With his new bill, he is accusing AIPAC of “lobbying and acting on behalf of the interests of Israel.”

AIPAC spokesperson Deryn Sousa responded to that charge by yoking Massie to Israel-critical Democrats, saying the lawmakers have long “tried to demonize millions of Americans, including thousands of AIPAC members in Kentucky's Fourth District, for advocating that America stand with an ally that makes us safer, stronger, and more prosperous.”

Israel-friendly groups have targeted Massie before. Days before Massie’s 2024 primary, AIPAC’s super PAC dropped $300,000 on ads assailing the representative for being “hostile to Israel.” RJC backed a primary challenger in his 2020 race, but later rescinded its endorsement and PAC support for Todd McMurtry after problematic social media posts surfaced.

But Trump’s involvement this round ratcheted up the stakes — and unleashed an unprecedented amount of spending.

RJC Victory Fund has unloaded more than $4 million on a sextet of ads attacking Massie over his opposition to the joint U.S.-Israel war in Iran and promoting Trump’s endorsement of Gallrein. It’s the most the group has ever spent in a House primary, according to AdImpact. AIPAC, meanwhile, has put almost $5 million behind a trio of spots slamming Massie for siding with progressive Reps. Alexandria Ocasio-Cortez (D-N.Y.) and Ilhan Omar (D-Minn.) in rejecting pro-Israel resolutions, including ones reaffirming U.S. support for Israel after Hamas’ Oct. 7, 2023, attack and condemning an Iranian drone attack on the country in 2024. Their combined spending has helped propel Massie’s primary into the record books, eclipsing the more than $25 million in combined ad spending tracked by AdImpact when pro-Israel groups groups successfully targeted Rep. Jamaal Bowman (D-N.Y.) in 2024.

It’s a more direct approach than AIPAC has taken in other races this year. And it reflects the different political realities the bipartisan group is facing depending on which side of the aisle it’s playing, as the deeply divided Democratic base openly wars over AIPAC after its interventions in New Jersey and Illinois.

“AIPAC’s views on Thomas Massie are no secret,” Dorton said. “We use different tactics in different districts. Our goal is to win.”

Several prominent donors who are supportive of Israel have also bankrolled the MAGA KY super PAC started by former Trump campaign manager Chris LaCivita and pollster Tony Fabrizio, including $1 million from hedge fund manager Paul Singer and $750,000 from a super PAC linked to casino magnate Miriam Adelson. Another group, the Christians United for Israel Action Fund, has spent six figures on billboards targeting Massie. A representative for Singer declined comment on the record. LaCivita and representatives for Adelson and Christians United for Israel Action Fund did not respond.

The glut of outside spending has caught the attention of some of the GOP’s biggest Israel critics.

Two weeks out from the election, Massie traveled to Maine to appear on Carlson’s podcast for a lengthy segment in which the two bashed Israel-aligned groups’ efforts to influence the race. James Fishback, a longshot candidate for Florida governor who has been sharply critical of Israel’s actions in Gaza and U.S. aid to its ally, endorsed Massie this week. Fishback told POLITICO that he views the deluge against Massie — who is “not some hardline Israel skeptic” — as a sign Israel supporters are “on their last legs.”

The race has generated some explicitly antisemitic moments as well.

Hold The Line PAC, a group that says it is focused on election integrity, ran a pro-Massie ad claiming Gallrein was “bought and paid for by the LGBTQ mafia.” The ad focuses on Singer, who is Jewish, and shows an unexplained rainbow Star of David in the background. The group did not immediately respond to a request for comment on why the image was included. Tim Murtaugh, an adviser to Gallrein’s campaign, said “this is just sad” in a statement in response to the ad.

And the son of Sen. Rand Paul (R-Ky.), a close Massie ally, drunkenly lobbed antisemitic insults at Rep. Mike Lawler (R-N.Y.), who is not Jewish, over the race while at a Capitol Hill bar this week, according to NOTUS. William Paul later apologized. Massie has not publicly addressed the ad or the Paul-Lawler incident.

Surveys show a competitive race. Gallrein pulled ahead of Massie by 8 percentage points in a Quantus Insights poll released Wednesday, after the incumbent narrowly led earlier surveys. But a Big Data Poll released Friday showed Massie up by 1 point.

The slim margins show Trump’s imprimatur and the outside spending it unlocked have elevated the first-time federal candidate into a formidable contender.

Michael Antonopoulos, who is advising Gallrein’s campaign, knocked Massie in a statement, saying the representative made the choice to poke the president in the eye every day, oppose his agenda, and take campaign cash from Obama, Biden, and Harris donors. Kentucky is fed up with Thomas Massie’s act and is ready to call in the Navy SEAL.”

But even Massie’s detractors acknowledge it will be difficult to pick off an incumbent — particularly one with entrenched support in a district that mirrors his libertarian streak.

“If he wins, the battle will continue,” said Sam Markstein, the RJC’s national political director. “But we do not expect that to be the case. We expect to win on Tuesday.”