The first three nights of the Republican convention turned in a halfhearted and largely unsuccessful effort to draw Donald Trump closer to the party he conquered. The final night was the one in which he fully consummated his conquest.

Trump’s acceptance speech was one of the most memorable and important ones ever delivered at a convention because it reflected a conscious effort to alter the ideological orientation of the party to which it was delivered to what Pat Buchanan, a sympathetic observer from a previous era, has bluntly and pithily called “ethnonationalism.”

Ethnonationalism is a form of conservatism, but the two philosophies diverge in ways that can leave their adherents bitterly at odds. Programmatically, ethnonationalists differ from standard-issue Republicans like George W. Bush or Paul Ryan in that they oppose free trade and immigration. Their orientation is nostalgic rather VII PHOTO than glitter-eyed about the future. Like traditional conservatives, they distrust federal power, but they extend their circle of rhetorical enemies to include the corporate elite. Most important, unlike standard conservatives, who tend to disregard race, ethnonationalists have a deeply, explicitly racialized view of the world.

All those ideological markers appeared in Trump’s address. The speech focused on four issues: crime, trade, immigration, and terrorism. The first three are issues most Republicans have deemphasized, or on which they have moved away from the direction advocated by Trump. The last, terrorism, he presented less as a foreignpolicy problem—the usual Republican take—than as an outgrowth of an immigration policy he believes should exclude Muslims. Virtually the entire speech was therefore consumed with what, from the standpoint of almost any traditional Republican leader, would be heresy.