WASHINGTON — Bernie Sanders has clearly tapped a vein of economic populism, but the latest presidential primary exit polls — along with previous primary and caucus results — suggest a Democratic Party electorate unwilling to embrace the kind of leftward shift the Vermont senator proposes.

That, perhaps, as much as Hillary Clinton’s continued lopsided advantage with non-white voters, underscores Sanders’ steep challenge as he tries to cut into the former secretary of state’s ever-expanding delegate lead.

Clinton won four states Tuesday — with Missouri still too close to call — and ran up comfortable margins in Ohio, North Carolina and Florida. The outcome gives her a wider delegate lead than then-Sen. Barack Obama enjoyed over Clinton at this point in the pair’s extended 2008 primary battle.

Exit polls conducted for the Associated Press and television networks in all five states that held primaries Tuesday found Democratic electorates inclined to maintain the governing approach of the Obama administration.

At least half of all voters surveyed preferred a continuation of Obama’s policies, while no more than a third wanted policies that are more liberal. And at least 7 in 10 voters in each state thought Clinton has realistic policy approaches, while Sanders registered lower on that assessment across the board.

The proportion saying Sanders has realistic policies was highest in the two states where he came closest to Clinton — Illinois and Missouri — where about two-thirds of Democratic voters said Sanders has realistic policies. In North Carolina, only about half of Democratic voters said Sanders’ policies are realistic, and in Florida it was less than half.

That gap suggests Clinton may have found a winning argument in challenging the feasibility of Sanders proposals for things like universal health insurance and tuition-free colleges and universities.

But Tuesday’s results from states like Ohio and even Missouri — states with electoral and demographic profiles more similar to Michigan — suggests Sanders could have trouble sustaining the momentum, even as he maintains considerable support at the ballot box and in fundraising.

In both states, Sanders commanded his usual advantage among younger voters, but Clinton still managed to win a slim majority among white voters in Ohio (53-47) while limiting Sanders’ advantage among whites in Missouri (54-45).

Clinton led handily among self-identified Democrats in each state voting Tuesday, while Sanders led among independents, who make up a much smaller proportion of the Democratic primary electorate.

Those numbers help explain Sanders’ trouble capitalizing even where the electorates are sympathetic to his arguments on trade, a major factor in his Michigan win. In neighboring Ohio, where a majority said international trade costs jobs, Clinton won by double digits. In Illinois and Missouri, the two closest margins Tuesday for Democrats, Sanders performed better than Clinton among voters who said that international trade mostly takes U.S. jobs rather than creates them. But Democrats were still split on whether trade takes or create jobs, limiting Sanders’ benefit.

Sanders’ struggle to capitalize on voter angst does not translate to the dynamics among Republicans, where front-runner Donald Trump continued to take advantage of voters who express general anger. The billionaire businessman rode the success to three victories, with Missouri still too close to call and Ohio siding with its home-state governor, John Kasich.

In Florida, where Trump trounced home-state Sen. Marco Rubio, about 59 percent of angry voters supported the billionaire, while just 16 percent supported Rubio.

In Ohio, Trump had a smaller, 51 percent to 29 percent margin over Kasich among that group. In Ohio, Kasich was supported by over half of voters who were just “dissatisfied,” but in Florida even that group gave Trump a slight advantage, 41 percent to 32 percent over Rubio.

Trump was the overwhelming favorite in each state among voters looking for an outsider. But Kasich won three-quarters of Ohio voters preferring the next president have political experience, while only just over half of those voters supported Rubio in Florida. Nearly a quarter of Florida GOP primary voters said they most value a candidate who “tells it like it is.”

For all their advantages, there are warning signs for both Clinton and Trump on distrust within their own parties. Majorities of Democrats each state said Clinton is honest, but in every case they were even more likely to say Sanders is honest.

Among Ohio Republicans, meanwhile, 54 percent said they believe Trump is not honest, while 44 percent of Florida Republicans made the same assessment. Forty-five percent of Ohio Republicans said they would consider a third party option in a Clinton-Trump matchup in November, while just 3 in 10 Florida Republicans said the same.