WILMINGTON, Del., - U.S. President Joe Biden cast an early vote in the crucial Nov. 8 midterm elections on Saturday, joined by his granddaughter Natalie, a first-time voter, and said he would visit more states in coming days to help Democrats fight for every possible vote.

Polls suggest Democrats could lose control of both houses of Congress, with voter discontent over high inflation spoiling the momentum Democrats had hoped to win from a bitter fight with Republicans over abortion rights.

"I'm feeling good," Biden told reporters after voting and speaking briefly with an elderly woman in a wheelchair. He said he had been to 36 constituencies already and would make another visit to the battleground state of Pennsylvania next week.

He said visits were also planned to New Mexico and California, as well as Maryland - and his key message would be that voters faced a fundamental choice that could profoundly change the next decades.

"I'm going to be spending the rest of this time making the case that this is not a referendum. It's a choice, a fundamental choice," Biden said. "It's a choice between two very different visions for the country."

"Democracy is literally, not figuratively, on the ballot this year," Biden told supporters at a $1 million Democratic fundraiser in Philadelphia on Friday, where he also condemned those who have persisted in spreading lies that the 2020 presidential election was stolen.

Biden repeated his concern about the brutal attack on the husband of House Speaker Nancy Pelosi and said it had likely been fueled by lies and "malarkey" about the election.

"The talk has to stop. That’s the problem. That’s the problem. You can’t just say, 'We’re mad about the violence, we condemn it,' condemn what produces the violence,” Biden said.

Nathan Brand, spokesman for the Republican National Committee, predicted widespread Republican ballot victories.

"Millions of Americans are casting their ballots against Biden and Democrats' reckless agenda of crime, rising prices, and open borders," he said.

Experts say voter turnout - usually far lower in midterm elections than in presidential ballot years - will be a critical factor in battleground states, and Democrats are urging voters to cast their ballots early.

A total of 19,495,342 early votes have been cast nationwide, according the U.S. Elections Project.

Some 8.3 million voters who turned 18 since the previous general election in 2020 are eligible to vote in this year's elections, according to the non-partisan Center for Information and Research on Civic Learning & Engagement at Tufts University.

The center estimates that 50% of young people aged 18-29 voted in the 2020 presidential election, an 11% jump from 2016, but turnout tends to drop off in non-presidential years.

(Reporting by Andrea Shalal; editing by Diane Craft and Nick Zieminski)