INDIAN WELLS, Calif. — Republicans might have won decisively up and down the ballot in November, but the party’s elite is already girding for the next fight: a fundamental clash of ideas within the GOP.

Such was the mood among some of the country’s influential conservative leaders and donors who convened over the weekend in this desert resort to discuss strategy for the Trump administration at a seminar hosted by the Koch political network.

The network believes it’s well-positioned to win or shape some of the flagship legislative battles to come, including health care and tax reform, and many attendees characterized this political moment as a singular opportunity to effect policy change, with Republicans in control of Congress and the White House.

But they also fear that they are losing a bigger war of ideas, both in Washington and among voters, and spoke with concern of the prevailing political currents that swept Donald Trump into the White House.

The Koch network has long championed a conservative approach to government — one now at odds with the populist and nationalist ideologies for which President Trump has become a powerful avatar. Inside the White House, chief strategist Steve Bannon and senior policy adviser Stephen Miller have begun to advance those ideas into policy, suggesting a level of ideological commitment that Trump’s campaign did not.

On the one hand, Trump’s brand of nationalist populism has raised serious policy concerns for the Koch group and others of their ilk on issues including trade and immigration reform. But the network is also beginning to sound an alarm on the broader socio-political environment, warning of a nation they see as careening toward “authoritarianism.”

“We have a tremendous danger,” Charles Koch said during one session this weekend, “because we can go the authoritarian route, or we can move toward a free and open society.”

Charles Murray, a political scientist who delivered remarks to donors during another session, echoed this concern: “Completely apart from the individual person of the president, I think we see an environment that is fertile for authoritarianism in the United States now.”

In the past, Murray said, Republicans and Democrats had together defended a shared idea of American values. “The American creed was the basis of individualism and freedom and opportunity,” he continued. “And what we discovered last year was that the proportion of the American electorate on the right that is still devoted to those American creedal principles is way smaller than I thought it was.”

Koch previously noted these dynamics in a Wall Street Journal op-ed, which was published on the day Trump accepted the Republican nomination for president at the party convention in Cleveland.

“The U.S. is already far down the path to becoming a less open and free society,” Koch wrote, “and the current cultural and political atmosphere threatens to make the situation worse: Growing attacks on free speech and free association, hostile rhetoric toward immigrants, fear that global trade impoverishes rather than enriches, demands that innovators in cutting-edge industries first seek government permission.”

Even during the few days of the Koch confab, these fears came into sharp focus with the president’s executive order banning refugees, immigrants and visitors from certain countries, restrictions that also initially ensnared some legal U.S. residents.

“We believe it is possible to keep Americans safe without excluding people who wish to come here to contribute and pursue a better life for their families,” said Brian Hooks, co-chairman of the Koch network of political groups. “The travel ban is the wrong approach and will likely be counterproductive.”

Trump and many congressional Republicans, meanwhile, have defended the policy, although some party lawmakers called for the order to be clarified and narrowed.

And the administration isn’t likely to slow or shift its course from here. Such policy initiatives are at the philosophical core of the new administration. Bannon, in a recent email to the Washington Post, touted “populist nation-state policies that are supported by the vast and overwhelming majority of Americans, but are poorly understood by cosmopolitan elites in the media that live in a handful of our larger cities.”

This view of the world is deeply unpopular within the Koch network, not only because its membership happens to be elite. (The more than 550 donors who gathered at Indian Wells give at least $100,000 each annually to the group, and many of them donate much more.)

“Populism is called populism for a reason. It’s popular thought, it’s not intelligent thought,” said Frayda Levy, a Maryland-based donor who attended the retreat. “These are simplistic ideas that resonate.”

Indeed, the network acknowledges the political pull of a message tailored to disaffected workers: One session during the gathering aimed to help donors “understand the root causes of the American people’s frustration and discontent.”

But the Koch network is also actively looking to push back on the populist ideas that have taken root amid that frustration and discontent. “That’s what we’re here to do,” Levy said.

The groups’ messaging in this regard could be brought to bear on a host of policy outcomes. Will they be able to persuade the public, for example, that a border tax would hurt American consumers, as the group has warned? Or that trade deals like the scrapped Trans-Pacific Partnership could benefit American workers?

“The conversation [on trade] has probably gone in the wrong direction,” conceded Andy Koenig, vice president of policy for Freedom Partners, one star in the constellation of Koch political groups, “and I think maybe folks in our center-right movement had taken for granted that we had won the war on trade, and not necessarily understood the amount of consternation that folks had about it.”

Shifting public opinion won’t be easy, although the network can tap a sprawling national grassroots web and deep pockets. The Koch network now must contend with populist, nationalist messaging that has the full force of the federal government behind it, in addition to Trump’s unique megaphone on social media and other channels.

It is also unclear whether the White House will be open to hearing them out. Koenig, asked if he’d aired his concerns about trade policy with the administration, said he has not spoken at all with the trade team. The Koch network did engage in some “very civil” policy discussions with Trump’s camp during the campaign, said Mark Holden, a Koch Industries executive, “so I don’t think it will be a problem at all.”

The administration has hired a few allies and alums of the Koch world who would be natural liaisons, including Marc Short, a former top political adviser in the Koch network who will now lead legislative affairs for the White House. Vice President Mike Pence, too, is viewed as an ally by Koch leaders.

But if the first few days of the administration are predictive, Trump and a small cadre of advisers will be driving the ship — an alarming thought to some of the influential donors at the weekend confab.

“It seems pretty clear [Trump] doesn’t understand policy,” Levy said. Nor is the influence of the president’s advisers a comforting factor. Levy worried, for example, that Bannon could use his position to promote populism at home and in Europe.

“Of course I worry,” Levy said. “I worry about that guy a lot.”