Sen. Joe Manchin (D-W.Va.) voiced skepticism on Tuesday over a Democratic push to change the filibuster along party lines, warning that his “preference” is for any rules changes to be bipartisan. 

"Being open to a rules change that would create a nuclear option, it's very, very difficult. It's a heavy lift," Manchin told reporters when asked about using the "nuclear option," in which Democrats would change the 60-vote legislative filibuster on their own.

"I'm talking. I'm not agreeing to any of this. ... I want to talk and see all the options we have open," Manchin said, adding that it was his "preference" that any rule changes have Republican support.

Manchin's comments come as Senate Majority Leader Charles Schumer (D-N.Y.) has vowed to force a vote on changing the rules by Jan. 17 if Republicans block voting rights legislation, as they are expected to.

"As I said in my 'Dear Colleague' earlier this week, if Republicans continue to hijack the rules of the chamber to prevent action on something as critical as protecting our democracy, then the Senate will debate and consider changes to the rules on or before Jan. 17, Martin Luther King Jr. Day," Schumer said from the Senate floor on Tuesday.

But to change the rules without GOP support would require total unity from all 50 members of the Senate Democratic Caucus. Both Manchin and Sen. Kyrsten Sinema (D-Ariz.) have warned for months that they are supportive of the current 60-vote threshold.

Manchin has long opposed using the nuclear option and added on Tuesday that if Democratic senators "go it alone" to change the rules, "it ends up coming back at you pretty hard."

Democrats previously used the nuclear option to change the rules in 2013 to confirm executive nominees and lower-level court nominees with a simple majority, though Manchin opposed using the nuclear option at the time. Republicans then used the nuclear option to lower the threshold for Supreme Court nominees in 2017 and to cut the debate time needed for most nominees in 2019.

There's growing support within the Senate Democratic Caucus to change the legislative filibuster, which requires 60 votes to advance most legislation in the Senate.

A group of senators tapped by Schumer have been in talks with Manchin about potential rules changes and those negotiations are expected to continue this week.

One idea that has been floated would create an exemption from the filibuster for voting rights legislation. Manchin, however, on Tuesday appeared skeptical that it wouldn't just nix the filibuster entirely.

"Anytime there's a carveout, you eat the whole turkey. There's nothing left," Manchin said.

Other ideas being floated include a talking filibuster, getting rid of the 60-vote hurdle needed to start debate on the bill but keeping in place that same hurdle on ending debate or moving from 60 votes needed to break a filibuster to 41 "no" votes being needed to sustain it.

"You know we're still having ongoing conversations as far as voting because I think the bedrock of democracy is making sure that you're able to cast a vote," Manchin said. "Let's just see. Conversations are still ongoing."