Senate Democrats are focused on protecting voting rights ahead of Thursday’s one-year anniversary of the Jan. 6 attack on the Capitol, but the caucus is a long way from sorting out the procedural mechanics of how to pass legislation without Republican support.

Senate Majority Leader Charles E. Schumer, D-N.Y., on Tuesday reiterated his commitment for the Senate to consider, no later than Martin Luther King Jr. Day, Jan. 17, a rules changes that would clear the path for a majority to approve voting rights legislation. He said it was clear that given opposition from Minority Leader Mitch McConnell, R-Ky., there would be no path that would get the 60 votes needed to break a filibuster under the current rules.

“It’s well known in our caucus and McConnell’s caucus, in the Republican caucus, that McConnell said it’s a bottom line: Nobody should cooperate on voting rights,” Schumer said. “So, there’s not going to be any kind of bipartisan action. We know that.”

As senators made their way back to the Capitol Tuesday following a Monday snowstorm that caused travel delays throughout the region, it was unclear whether Democrats would ultimately reach an agreement on any kind of go-it-alone procedural changes.

But leaving a meeting Tuesday evening, Sen. Joe Manchin III, D-W.Va., hinted at some of the changes that could be on the table. They include an effort to limit filibusters of motions to proceed to legislation and a requirement for talking filibusters — where objecting senators actually have to hold the floor.

“We’re just looking at every part of history that we can to find out if there’s something that gives us a pathway forward,” Manchin said. “That you can have a good discussion, and good debate, and then good amendment process.”

One of the historical examples the West Virginia Democrat cited was the Senate’s debate in the 1970s over whether the three-fifths of senators needed to break a filibuster should be three-fifths of the Senate (60, in most cases) or three-fifths present-and-voting.

“Three-fifths of voting puts pressure on both sides,” he said. Such a change would make it difficult for objecting senators to simply register their opposition and go home, as is overwhelmingly the case now.

“The need for us to protect democracy as we know it, and the Senate as it has operated for 232 years are extremely, extremely high bars that we must be very careful if we’re willing to cross those,” Manchin told reporters earlier in the day.

But Manchin, who has backed versions of the substantive legislation Schumer and the Democratic caucus is seeking to advance on voting rights, is more circumspect about trying to create an exception from the rules to allow Democrats to bypass the Republicans with a simple majority vote on that particular issue.

“The reason I say it’s a heavy lift is that once you change a rule, or you have a carve out, I’ve always said this, any time there’s a carve out, you eat the whole turkey,” Manchin said.

McConnell, in a floor speech Tuesday, appeared to be echoing Manchin’s concerns, as well as those expressed by Arizona Democratic Sen. Kyrsten Sinema and other members of the Democratic caucus over the years.

“There are senators on both sides who understand that the entirety of federal law shouldn’t go radically boomeranging back and forth every time the Senate narrowly changes hands,” the minority leader said.

Senate Republicans like Minority Whip John Thune, R-S.D., contend that there is no way a carve out for a single policy area will hold.

“It’s called the nuclear option for a reason and I think it represents, you know, Armageddon in terms of the Senate’s operations and functions and what the Senate is all about,” Thune said Tuesday.

When asked about the possible changes to rules and precedents, Thune was ready with a statistic that will likely be repeated in the coming weeks. Thune said that under the Republican Senate majority with then-President Donald Trump, “34 different occasions he came after us to get rid of the filibuster, and we said no.”