On Tuesday, a passionate opponent of American involvement in overseas wars squares off against pro-Israel groups who accuse him of antisemitism and have heavily outspent him in a contentious primary race.

The catch? While virtually all of the big spending on U.S.-Israel policy in recent years has been in Democratic primaries, this time the candidate in question, former Rep. John Hostettler, is a Republican.

Hostettler is vying for the GOP nomination in Indiana’s 8th Congressional District, a solid Republican seat in the Hoosier State’s southwestern corner which he previously represented from 1995 to 2007. Some pro-Israel donors also backed the conservative Democrat who unseated him in 2006.

His chief opponent is state Sen. Mark Messmer, who has attracted the support of deep-pocketed outside groups concerned about Hostettler’s record on Israel and comments about the Jewish identities of policymakers involved in planning the Iraq War.

Hostettler is defiant. In an April Facebook post that employed antisemitic tropes, the former congressman joked that the pro-Israel groups spending against him are “DEFINITELY NOT a cabal.”

The Republican Jewish Coalition’s super PAC has spent nearly $1 million boosting Messmer on the airwaves.

Matt Brooks, executive director of the Republican Jewish Coalition, said that Hostettler’s out-of-print 2008 book, “Nothing for the Nation: Who Got What Out of Iraq,” promoted “centuries-old antisemitic tropes about the influence of Jews in politics.”

“He was consistently one of the most anti-Israel votes in Congress,” Brooks added. “There’s not a lot of ambiguity there.”

The American Israel Public Affairs Committee’s super PAC, United Democracy Project, has also spent nearly $1.3 million attacking Hostettler. Hostettler is the first Republican candidate to be on the receiving end of UDP’s money cannon since AIPAC created the group in 2021.

Patrick Dorton, a spokesperson for UDP, likened Hostettler to Rep. Thomas Massie (R-Ky.), another libertarian-minded paleoconservative whose opposition to foreign aid, including to Israel, has earned him AIPAC and UDP’s ire.

“Hostettler was the Tom Massie of his era when he was in Congress, virulently anti-Israel,” Dorton said in a statement. “Our focus is not letting detractors of the U.S.-Israel relationship of either party be elected to Congress. Hostettler has a terrible record on Israel and doesn’t reflect the views of his constituents on the issue.”

Although United Democracy Project’s goal is to elect candidates aligned with its pro-Israel mission, it has generally avoided mentioning Israel policy in its ads in Democratic primaries. That’s likely because Democratic primary voters in most districts would not base their vote on a candidate’s Israel record, and are generally more critical of Israeli policy than AIPAC or UDP.

But in a Republican primary, where voters are staunchly pro-Israel and more likely to see it as a salient issue this year, the calculus is different. One of UDP’s TV ads focuses entirely on Hostettler’s Israel record. “What kind of Republican votes against supporting Israel?” the narrator asks as ominous music plays. “John Hostettler did.”

In the 30-second spot, UDP highlights not only Hostettler’s annual votes against foreign aid spending, including to Israel, but also his status as one of nine House Republicans to vote against an October 2000 resolution condemning Palestinian terrorism and expressing support for Israel at the start of the Second Palestinian Intifada.

Of course, the race has attracted outside money from other sources as well. Messmer, the preferred candidate of the pro-Israel groups, also has the support of the super PAC America Leads Action, a group funded by Walmart heir Rob Walton that has spent over $1.5 million attacking Hostettler.

Hostettler has not been entirely without outside help either, though his funding pales in comparison to Messmer’s. The American Leadership PAC, whose top funder is Tom Klingenstein, chair of the Claremont Institute, an “America First” think tank, has spent over $230,000 on advertisements for Hostettler. And the Protect Freedom PAC, which is backed by pro-Israel private equity billionaire Jeffrey Yass, has spent nearly $500,000 on Hostettler’s behalf.

Amid Israel’s invasion of Gaza, which has killed more than 34,000 Palestinians, debate has raged over when Israel criticism veers into antisemitism.

Although Israel supporters have mainly trained their fire at critics on the left, Hostettler is part of a long history of paleoconservatives whose statements about the U.S.-Israel relationship have gotten them in hot water.

Like Massie, Hostettler has questioned Israel supporters’ loyalty to the United States. And like prominent paleoconservative Pat Buchanan, he believed that proponents of the Iraq War were promoting Israel’s interests over those of the United States.

Hostettler’s 2008 book, “Nothing for the Nation,” is out of print, and not available for order at major online book retailers. Hostettler’s critics mostly reference excerpts of the book cited in a scathing 2008 column in the Jewish Standard about it by Abe Foxman, then-national director of the Anti-Defamation League.

Hostettler zeroed in on Jewish Bush administration Pentagon official Douglas Feith’s founding of a law firm with “Marc Zell, who was a resident of Israel,” italicizing the words for emphasis, according to Foxman.

Foxman also quotes Hostettler as recounting a time when he asked, “Why did Messrs. [Paul] Wolfowitz, Feith, [David] Wurmser, [Abram] Shulsky, and [Lawrence] Franklin fashion intelligence in support of the spurious claim of the presence of a WMD program in Iraq to draw the United States into a conflict that would lead to the demise of the regime of Saddam Hussein?” The answer he received was, “‘In the defense of the nation Israel.’”

Many neoconservative proponents of the Iraq War were Jewish, but the top policymakers in charge at the time ― President George W. Bush, Vice President Dick Cheney and Secretary of Defense Donald Rumsfeld ― were not Jewish.

Rather than seek to clarify his intentions, Hostettler doubled down on questionable innuendo in a Facebook post in early April. He was responding to an article in Jewish Insider about AIPAC’s super PAC launching an ad blitz against him.

Hostettler repeatedly describes Foxman as a rabbi even though he is not, and mocks the ADL as the ADLF — “Anti-Defamation of Leo Frank.” Leo Frank, the sole Jewish person to be lynched in the United States, was kidnapped from his prison cell by a mob that murdered him in Georgia in 1915. The historical consensus is that Frank, a pencil factory superintendent in Atlanta, was wrongfully convicted of the murder of a young girl, but Hostettler is apparently sympathetic to revisionist histories of what occurred. (Frank’s trial was one of the reasons for the ADL’s founding in 1913.)

Then Hostettler quotes a part of the Jewish Insider article recounting that a “loose network” of donors with “strong ties to AIPAC” supported the Democratic challenger who unseated Hostettler in 2006.

“Friends, help me out here. I’m thinking of a word. That word is often used to describe the work of ‘a loose network’ of persons with ‘strong ties’ to an organization who ‘organize against’ one person to defeat that person’s goal,” Hostettler wrote sarcastically. “It’s on the tip of my tongue. I mean, it’s right there. Oh! Don’t worry. It’ll come to me, I’m sure.”

“Who knows? Maybe they’ll be successful again,” he added. “And by ‘they’ I mean that ‘loose network’ — that doesn’t seem quite as ‘loose’ today as in 2006 — DEFINITELY NOT some ‘cabal.’”

But the primary in Indiana’s 8th is not just about charges of antisemitism. The rival ad campaigns also reflect a Republican proxy war over foreign policy that extends beyond Israel.

While both candidates emphasize their commitment to ending illegal immigration, and completing Trump’s border wall, the American Leadership PAC spot also notes Hostettler’s support for “ending billions in foreign aid to corrupt countries like Ukraine.”

“America First conservative John Hostettler will partner with President Trump to defeat the radical left and the weak RINOs in D.C.,” the spot also says.

A Protect Freedom PAC ad is narrated entirely by Sen. Rand Paul (R-Ky.), a fellow anti-interventionist whose father, former Rep. Ron Paul (R-Texas), worked alongside Hostettler in the House. Hostettler and the elder Paul were two of the six House Republicans who voted against authorizing the Iraq War in 2002.

As footage of Biden meeting with Ukrainian President Volodymyr Zelenskyy appears on-screen, Paul says he “trusts” Hostettler to “stop sending our taxpayer dollars overseas.”

It’s unclear how much either Messmer or Hostettler have themselves brought up foreign policy on the campaign trail. Both candidates’ campaigns have limited social media presences and did not respond to HuffPost’s requests for comment about their positions. The one TV ad available on Messmer’s YouTube page highlights his background as a businessman and engineer, as well as his “plan” to end birthright citizenship and “stop Biden’s inflation.”

Still, it’s clear from Hostettler’s record he represents the smaller, but growing wing of the Republican Party that sees anti-interventionism as an inextricable component of what it means to be a Trump-aligned, “America First” Republican.

There is a long tradition of opposition to U.S. entanglements in foreign wars on the American right. The school of thought, dubbed “isolationism” by its critics, has its intellectual roots in the famous John Quincy Adams speech that the U.S. “goes not abroad in search of monsters to destroy,” according to Kelley Vlahos, a senior adviser for the restraint-oriented Quincy Institute, and editorial director for Responsible Statecraft.

“He warned that going out and trying to create little Americas everywhere would actually come back and boomerang against our own liberty at home,” Vlahos said.

But the U.S.’s entry into World War II and the subsequent Cold War with the Soviet Union turned dovish conservatives into a minority faction within the Republican Party. The rise of the militant — and deeply pro-Israel — neoconservatives in the 1980s, and their prominence during the global war on terror in the 2000s, made figures like Hostettler dissenters — paleoconservatives hearkening to an older and less fashionable tradition.

If Hostettler and Ron Paul kept the paleoconservative foreign policy flame alive in Congress, figures like Buchanan, a former Republican White House aide and presidential candidate, shepherded the movement’s intellectual arm. Buchanan was a bitter skeptic of the U.S.’s unconditional support for Israel, and a rare and outspoken conservative voice against the Iraq War.

Trump’s nomination and election brought the foreign policy views of Buchanan and Hostettler back to the fore of the Republican Party. Once in office, the reality star-turned-populist commander in chief’s commitment to anti-interventionism was iffy at best, granting Ukraine lethal aid that former President Barack Obama had denied the country, tearing up the Iran nuclear deal, and backing Saudi Arabia’s brutal invasion of Yemen. But Trump’s broadsides against the Iraq War, his skepticism of NATO, his ambivalence about taking sides in the Russia-Ukraine war, and his general insistence on the primacy of narrow U.S. interests when considering action abroad have at least created the space for more Republicans in Hostettler’s mold.

“Hostettler was a bit ahead of his time, so to speak,” Vlahos said. “He was taking very unpopular views on foreign policy long before candidate Trump came along and made it OK to question the Iraq War.”

“Hostettler may be paying for it now,” she added. “But he has more company in the conservative base than he had before.”

The intellectual strain that Hostettler represents is enough for some of today’s self-described “America First” conservatives to regard the current barrage of attack ads against him as a purely ideological vendetta.

“It doesn’t happen often that anyone in Congress takes a really, really hard vote against their party,” said Ryan Girdusky, a populist Republican consultant, who thinks the opposition to Hostettler is due to his Iraq War vote. “He did. He was right when it was important to be right. And he never backed down from that.”