"It's the wrong piece of legislation to bring our country together and unite our country, and I'm not supporting that because I think it would divide us more. I don't want to be in a country that's divided any further," Manchin said on "Fox News Sunday."
"I think there's a lot of great things in that piece of legislation, but there's an awful lot of things that basically don't pertain directly to voting," the senator said.
The bill, also known as S1, is the largest overhaul of U.S. election law in at least a generation and covers many aspects of the voting process, including requiring states to automatically register eligible voters and offer same-day voter registration.
The measure also requires states to offer 15 days of early voting and allows no-excuse absentee balloting, which 14 states would have to implement. The states that already allow it would have to conform to S.1’s standards.
Manchin also detailed his opposition to the For the People Act in an op-ed in the Charleston Gazette-Mail.
"Do we really want to live in an America where one party can dictate and demand everything and anything it wants, whenever it wants? I have always said, ‘If I can’t go home and explain it, I can’t vote for it.’ And I cannot explain strictly partisan election reform or blowing up the Senate rules to expedite one party’s agenda," Manchin wrote.
Manchin reiterated his support for the filibuster in the op-ed.
"With that in mind, some Democrats have again proposed eliminating the Senate filibuster rule in order to pass the For the People Act with only Democratic support. They’ve attempted to demonize the filibuster and conveniently ignore how it has been critical to protecting the rights of Democrats in the past," he wrote.
Rep. Mondaire Jones, D-N.Y., pushed back against Manchin on Twitter and said the West Virginia lawmaker's op-ed should be titled, "Why I’ll vote to preserve Jim Crow." He also appeared on MSNBC and said the op-ed is "intellectually un-serious."
Meanwhile, Manchin and another bipartisan-minded Democrat, Sen. Kyrsten Sinema of Arizona, are facing pressure to support the voting reform bill.
A liberal dark-money group is launching advertisements in their home states in an attempt to get their constituents in West Virginia and Arizona to pressure them into supporting the For the People Act.
Fox News’ Houston Keene, Cameron Cawthorne and Joe Schoffstall contributed to this report.