Americans are confused and worried about elections. Will that impact turnout?

Voters arrive before casting their ballots at a polling location in Arlington, Va., on April 21. "This is my 22nd year [running elections]," one Colorado election official told NPR. "Absolutely, this is the most uncertain." Win McNamee/Getty Images hide caption

Take this summer's back and forth over President Trump's executive order to restrict mail voting, which bounced around the courts until it was ultimately halted by the Supreme Court last week.

But across the country this midterm year, local officials say they're hearing from voters confused by the process — and worried about potential federal interference in the election.

"'How is this going to work? How are you going to make sure my ballot is counted? How am I going to get my ballot?' — I'm hearing all of these things," said Carly Koppes, a local Republican voting official in Weld County, Colo.

When asked how this cycle compares to previous elections she's overseen, Koppes didn't hesitate.

"This is my 22nd year [running elections]," she said. "Absolutely, this is the most uncertain."

Fewer than 50% of voters say they expect the midterms to be "free and fair elections," according to polling this month by the University of California San Diego , although a new NPR/PBS News/Marist survey did find that three-fourths of voters trust their own state and local officials to run a fair election.

Four in 10 voters say they expect federal immigration enforcement agents to be present at polling places in their area, according to the UC San Diego survey, despite federal law banning armed federal troops from election sites.