Some reluctant Democrats consider ditching filibuster for voting bill despite grim prospects over changing rules

Democrats say they expect growing demands to change the filibuster rules later this month when the battle over voting rights heads to the Senate floor, hoping that the pressure will be enough to convince their party's most stalwart filibuster defender, Sen. Joe Manchin of West Virginia, to buckle and agree to gut the filibuster -- though he's showing no signs of caving.

Adding to that pressure is the expectation in the Senate that other long-time backers of the existing rules will change their views and back killing the requirement that 60 votes are needed to overcome a filibuster in order to ease passage of a measure Democrats argue would combat efforts to restrict access to voting.

One of them: Sen. Angus King, a Maine independent who has been among the handful of members in the Senate Democratic Caucus to embrace overhauling Senate filibuster rules to let legislation advance by a simple majority of 51 senators.

King is making clear that his view could indeed change if Republicans block the elections bill later this month, something he alluded to earlier this spring and made clear in an interview this week with CNN.

"We have to defend democracy," King said. "And I'm afraid that our colleagues have put us in that position. I'm very reluctant to modify the filibuster. But I don't feel I can stand by and see our system subverted."

Asked if he'd be open to backing the nuclear option -- a tactic to change Senate rules along straight party lines -- King said bluntly: "Yes."

Democratic sources told CNN they expect that more senators will join King and hope that will be enough to convince some holdouts to change their views. Several have been skeptical about changing the rules, including New Hampshire Sens. Jeanne Shaheen and Maggie Hassan, while others like Manchin and Arizona Sen. Kyrsten Sinema are steadfastly opposed.

Manchin opposes the Democrats' bill, the For the People Act, and he would not commit to voting to open debate on the legislation when it comes to a vote on the week of June 21. The support of 60 senators would be needed to break a filibuster to open debate, which almost certainly won't happen given stiff opposition from Republicans, who argue the bill would amount to a federal takeover of elections laws.

"We're still talking," Manchin told CNN last week, referring to his efforts to craft a bipartisan agreement on a narrower piece of legislation aimed at restoring a key aspect of the 1965 Voting Rights Act gutted by the Supreme Court eight years ago.

But even that idea, which Manchin is working on with Alaska GOP Sen. Lisa Murkowski, lacks the votes to clear a Senate filibuster.

Manchin has also refused to consider changes to the Senate rules that would make only make voting legislation exempt from a filibuster -- something that Democrats are increasingly pushing.

"I am adamantly opposed to dividing our country any further on anything that basically, such as a major policy change as that, goes down partisan lines and could be very detrimental, I think, very harmful to our country," Manchin said when asked about changing the filibuster rules.

Indeed, proponents of the filibuster -- such as Manchin -- have long argued that the tool is designed to force the chamber into bipartisan consensus and prevent the Senate from turning into the majority-rules House. They warn that changing the rules now will come back to haunt Democrats when they find themselves in the minority.

Yet the pressure is only bound to be ratcheted up in the days ahead.

"I spent 23 years defending people's rights to vote around the world so I'm gonna choose defending Americans rights to vote over 100 senators to mount a filibuster any day," Democratic Sen. Tammy Duckworth of Illinois told CNN.

Asked about Manchin's concerns that gutting the filibuster would effectively blow up the Senate, Duckworth said, "They're blowing up the right of Americans to vote all across the country."