Donald Trump and Trumpism have transformed the Heritage Foundation and the Federalist Society, two institutions at the heart of the conservative legal movement. In this article, I use the conservative philosophy of fusionism as a lens for understanding the causes and consequences of the transformation. The original fusionism of William F. Buckley and Frank S. Meyer brought disparate factions of conservatives together under the mantle of libertarian means to conservative ends. Here, I show that Trump and Trumpism have transmogrified that original concept into a “new fusionism” of authoritarian means to Christian nationalist ends . I investigate the extent to which this “new fusionism” has been embraced or endorsed by the Heritage Foundation and the Federalist Society and what the consequences might be for the respectability and efficacy of the conservative legal movement after Trump.