There are moments when a political movement, however united it may appear, suddenly reveals its fault lines. It is not external adversaries that open them, but an internal tension, a debate that turns into a struggle for the soul of the group. Among the supporters of Donald Trump, this fracture has taken the form of a debate that should have remained marginal: antisemitism. And yet, it is precisely this that has triggered a crisis, not only moral but also political, at the heart of the Trumpist base.