Congratulations are in order for Donald Trump: His attack on Iran is the most unpopular American war in modern history. The New York Times compared support for Trump’s war with initial support for nine other wars going back to World War II, and found Trump’s adventure at the very bottom. The Times has support for it at 41 percent. Other calculations find support in the high 30s.This is heartening. It suggests the American public is far less reflexively disposed to accepting the case for war than in the past, as I’ve argued. But here’s a different reason this matters: It may deliver another blow to the idea that Trump’s 2024 win produced a national realignment.The war, it turns out, is particularly unpopular among some of the voter groups that Trump won over—young and nonwhite working class voters—the ones who gave rise to that oft-proclaimed “realignment thesis.”The numbers are striking. This week’s Quinnipiac poll finds that only 40 percent of voters support the war on Iran versus 53 percent who oppose it. I asked Quinnipiac for a demographic breakdown: Among voters aged 18 to 34, only 21 percent support the war with Iran, versus 71 percent who oppose it.Among nonwhite voters without a college degree, only 21 percent support the war, versus 69 percent who oppose it.Meanwhile, young voters say by 58 percent to 21 percent that Trump has made American leadership in the world “weaker” and not “stronger.” Nonwhite noncollege voters say the same by 62-23.Just after Trump’s 2024 victory, a ubiquitous interpretation held that those gains among young and nonwhite working class voters represented a generationally defining shift in American politics. A new “multiethnic, working-class party” was born. But events have undercut the thesis. Trump has lost enormous ground among those very voters due to the same persistent high prices that drove them to him, suggesting they never underwent any serious ideological transformation.Separately, the spike in positive views of immigration and the massive backlash to ICE—especially among young people—undermine notions of a deep cultural shift against immigrants, another blow to the seismic-realignment theory.Now let’s add Trump’s war to this equation. Here, young voters are particularly pertinent.Trump’s promise of “no more wars” unquestionably helped drive young people to him. JD Vance expressly cast this refrain as a message to the entire “young generation,” vowing relief from the “burden” of elite warmongering folly. No doubt many young people found this meaningful. Yet now Trump’s Iran adventure is resonating very badly with them.It’s a complicated story. John Della Volpe, a pollster who specializes in the youth vote, says that for young people, Trump’s promise had unappreciated resonance. Coming after the financial crisis and global Covid shock exacerbated economic precarity, lack of mobility and uncertainty about the future, Trump’s vow signified a deeper form of renewal at a time when young people’s faith in American institutions had been badly shaken.Trump’s successes among young voters were “largely built on the promise that he would create more, not less, stability in their lives,” Della Volpe said. Many of them see Trump’s war in Iran in that context, he continued, interpreting it as “clear evidence that institutions cannot be trusted” after all.This especially applies to young men. Della Volpe told me he just conducted over 50 interviews with men of ages 19 to 29 for a forthcoming release. They are registering “strong opposition” and dismay with Trump over the war, Della Volpe said, describing their message this way: “He assured them there would be no more wars, and it feels like betrayal.”These days it’s hard to recapture in one’s head the national atmosphere of disillusionment that the Forever Wars unleashed. But many people in their late 20s or early 30s today came of age politically while watching Americans come home in caskets and official pronouncements about the wars utterly disintegrate. In a sense, Trump’s economic failures and Iran invasion constitute a double-whammy of broken promises. He gave young people hope for a brighter economic future rooted in populist nationalist renewal and also hope for a future of peace.“Neither of those things has been delivered,” Della Volpe said.There’s another layer of betrayal worth dwelling on here. While Trump’s no-new-wars vow is often cast as a break with the Bush-era neoconservatism of the Forever Wars, the Times’s Ross Douthat sees a hidden continuity between that doctrine and MAGA ideas today. Just like the right back then, the new Trumpian right is preoccupied with “civilizational decadence” that can be arrested with awesome, revitalizing displays of American techno-military prowess.Both display a similar “hubris,” Douthat writes.