“We are nationalists, not white nationalists,” David Brog, one of the organizers, said in his welcoming remarks , calling any equation of the two “a slander.” He then pointed to the door and invited anyone who “defines our American nation in terms of race” who had slipped through the conference’s careful screening to leave.

But inconveniently, just a few hours earlier, President Trump had let loose with tweets calling for four freshman congresswomen of color to “go back” to the “broken and crime infested” countries they came from, throwing an awkward wrench into the messaging.

Not that Mr. Trump’s name was mentioned in the program or the mission statement for the event, which was organized by the Edmund Burke Foundation, a newly formed public affairs institute. It featured headlining speeches by Tucker Carlson, John Bolton and Peter Thiel, as well as some three dozen speakers on panels covering topics like immigration, foreign policy and economic nationalism. The names of Burke and Lincoln may have been uttered as much as the president’s.

Conservatives have always prided themselves on being driven by ideas, and the big idea here was that nationalism — shorn of its darker associations — could provide an intellectual banner now that the conservatism based on free trade, libertarian economics and military interventionism t hat held sway for decades has run out of gas.

“Today is our independence day,” Yoram Hazony, an Israeli political theorist, author of the recent book “The Virtue of Nationalism” and the conference’s intellectual prime mover, declared in his fiery opening remarks. “We declare independence from neoconservatism. We declare independence from neoliberalism, from libertarianism, from what they call classical liberalism.”