After addressing more than 3,400 Nebraska residents in Omaha Friday evening, U.S. Sen. Bernie Sanders on Saturday made his second stop on his National Tour to Fight Oligarchy—telling Iowa City, Iowa residents that “Trumpism will not be defeated by politicians inside the D.C. Beltway.”

“For better or worse, that is not going to happen,” said the Vermont Independent senator, whose broadly popular policy proposals have long been dismissed by Democratic leaders as unrealistic and radical while President Donald Trump has increasingly captured the attention of the working class Americans who would benefit most from Sanders’ ideas.

“It will only be defeated by millions of Americans in Iowa, in Vermont, in Nebraska, in every state in this country, who come together in a strong grassroots movement and say no to oligarchy, no to authoritarianism, no to kleptocracy, no to massive cuts to programs that low-income and working Americans desperately need, no to huge tax breaks for the wealthiest people in this country,” said Sanders.

The senator announced his tour earlier this month as Elon Musk, the head of the Trump-created Department of Government Efficiency who poured $277 million on the president’s campaign, swept through numerous agencies, with DOGE staffers setting up illegal servers, seizing control of data, shutting federal employees out of offices, and working to shut down operations across the government.

Since Trump took office for his second term just over a month ago, roughly 30,000 federal employees have been fired or laid off—part of Musk’s push to cut $2 trillion in federal spending in order to fill the $4.6 trillion hole that Trump’s extension of the 2017 tax cuts would blow in the deficit.

Republican lawmakers have also pushed to include cuts to Medicaid, and Trump this week signaled he would back Medicare cuts after repeatedly insisting he would not slash the popular healthcare program used by more than 65 million Americans, in order to save money while handing out tax cuts to the same corporations and ultrawealthy households that benefited from the 2017 tax law.

“Today in America we are rapidly moving toward an oligarchic form of society where a handful of multibillionaires not only have extraordinary wealth, but unprecedented economic, media, and political power,” said Sanders in Iowa City, which like Omaha is represented by a Republican U.S. House member who narrowly won reelection last November and has faced pressure to reject the GOP budget plan. “Brothers and sisters, that is not the democracy that men and women fought and died to defend.”

Sanders began his tour in Omaha and Iowa City to pressure the Republican House members there—Reps. Don Bacon (R-Neb.) and Mariannette Miller-Meeks (R-Iowa) out of supporting the GOP’s proposed cuts.

“Together, we can stop Republicans from cutting Medicaid and giving tax breaks to billionaires,” said Sanders ahead of the Iowa City event.

Sanders drew loud applause when he noted that the increasingly oligarchic political system extends past just Trump, Musk, and Republican lawmakers.

“The role of billionaires in politics, it’s not just Musk, it’s others,” he said. “It’s not just Republican billionaires, it is Democratic billionaires. It is the corruption of the two-party system.”

Progressive activists and journalists in recent weeks have expressed growing frustration with Democratic leaders as they have publicly appeared to throw up their hands and deny they have any power to fight Trump’s attacks on immigrants, transgender children, and other marginalized people.

House Minority Leader Hakeem Jeffries (D-N.Y.) has garnered scorn for meeting with Silicon Valley executives to “mend fences” with the powerful tech sector—where numerous CEOs have signaled support for Trump during his second term.

Ken Martin, the newly elected chair of the Democratic National Committee, said last month that the party should continue to take money from “good billionaires.”

Some Democratic senators have voted for Trump’s Cabinet nominees even as members of the caucus have accused Musk of orchestrating a coup on Trump’s behalf, and leaders including Jeffries have reportedly become “very frustrated” with progressive advocacy groups like Indivisible and MoveOn for organizing grassroots efforts to pressure the Democrats to act as a true opposition party.

Meanwhile, Sanders this weekend has captured the attention of thousands of people in Republican districts along with hundreds of thousands of people who have watched his anti-oligarchy tour online.

“The energy around what Bernie is doing is insane,” said Matt Stoller, a researcher at the American Economic Liberties Project. “It’s like there’s only one person who is actually able to sidestep the demoralization and frustration.”

Jeremy Slevin, a senior adviser to Sanders, reported that in Iowa City, the senator gave “not one, not two, but three different speeches to overflow crowds,” with 2,000 people lining up to see him speak “on a freezing cold day in a Republican district.“

Pointing to the enthusiasm shown in Nebraska and Iowa, Sanders supporters questioned the idea, reportedly embraced by Democratic consultants and politicians, that “Americans don’t understand the word oligarchy.”

“Bernie Sanders launched an anti-oligarchy tour, and it’s the only thing that has popularly resonated within the Democratic Party base,” said Stoller. “That’s fascinating and notable.”