By Gregory Krieg and Dan Merica, CNN

(CNN) -- The death of Supreme Court Justice Ruth Bader Ginsburg weeks before the presidential election has turned Democratic nightmares into a crushing reality.

Impervious to cries of hypocrisy and pleas to adhere to a standard they set in 2016, Republicans are bulling forward with plans to fast-track her replacement. Liberal hopes that enough GOP senators might stand in the way have been all but dashed with Utah Sen. Mitt Romney's announcement Tuesday that he supports a vote on President Donald Trump's eventual nominee.

The confirmation of a new justice appointed by Trump would establish a hard conservative majority on the high court, shifting its balance of power while immediately endangering the Affordable Care Act. The court could also emerge as a reliable mechanism of the right for undermining big ticket legislation passed by Democrats in the future, even if the party wins the presidency and control of Congress.

With that daunting prospect in mind, long simmering conversations on the left over the merit and possibility of abolishing the legislative filibuster, which could pave the way for expanding the number of seats on the Supreme Court and pursuing statehood for Washington, DC, and Puerto Rico, have been elevated into the mainstream. Many top Democrats, including moderates like Senate Minority Leader Chuck Schumer of New York, are repeating a new mantra: "Everything is on the table."

The momentum behind the push, though, has already run up against the cautious nature of former Vice President Joe Biden, once a long-serving senator and ardent institutionalist who has come out in the past against changing the current rules.

Asked on Monday by a reporter in Wisconsin if he would consider packing the court in a tit-for-tat with Republicans, Biden demurred.

"It's a legitimate question, but let me tell you why I'm not going answer," Biden said. "Because it will shift the focus. That's what (Trump) wants, he never wants to talk about the issue at hand and he always tries to change the subject."

During the primary, Biden consistently opposed any suggestion that Democrats might expand the court in an effort to restore its partisan balance, suggesting it was a flawed tactic that would only exacerbate the problem it intended to solve. And his campaign has, from the start, hinged on a promise to repair relationships on Capitol Hill -- not effectively giving up on them in favor of the hardball tactics that the modern GOP has embraced.

Going forward, Biden's team is determined to frame the campaign's central debate on health care and what the seating of a new conservative justice would mean for the future of Obamacare. The court is scheduled to hear a GOP-backed case to strike down the law, including its protections for people with pre-existing conditions, a week after the election.

This past weekend, Biden, in a speech on the Supreme Court fight, excoriated Republicans over what he described as "an exercise in raw political power" before stressing his focus on efforts to defeat the coming nomination through more conventional means. Delaware Sen. Chris Coons, a close confidante, refused to directly address the prospect of court-packing during a Fox News interview on Sunday, suggesting the best path forward for Democrats lies in appealing to their GOP Senate colleagues' better angels.

The push to abolish the legislative filibuster, which effectively requires a 60-vote supermajority to pass any bill out of the Senate, got a boost from former President Barack Obama, still the party's most popular and influential figure, when he endorsed it during his tribute to the Civil Rights icon John Lewis, at the late Georgia congressman's funeral in July.

"If all this takes eliminating the filibuster, another Jim Crow relic, in order to secure the God-given rights of every American, then that's what we should do," Obama said, backing a range of democracy reforms, including new voting rights legislation, statehood for Washington, DC, and Puerto Rico, automatic voter registration and an end to partisan gerrymandering.

Obama's remarks were a sort of vindication -- and stamp of approval -- for other Democrats with roots in the party establishment who have been pushing for a more aggressive posture.

Divisions within the party

Brian Fallon, a former top aide to Hillary Clinton in 2016 and the head of Demand Justice, a Democratic group aimed at fighting Trump's judicial appointments, said that the party needs to realize that victory in November will not "change everything."

"We have a broken system, so we have to think bigger," Fallon told CNN. "And all these issues Democrats care about ... just winning the election is not going to be enough to make progress on those things."

And pledging to go big on reforms to the democratic process could be a key to unlocking the current situation.

"Democrats have to create some leverage for themselves," said Fallon, who has previously worked for Democrats like Schumer and former Attorney General Eric Holder. Republican Senate Majority Leader Mitch "McConnell has the numbers in the Senate. If he wants to be shameless now, he can be."

Demand Justice has been advocating for expanding the court for years. But Fallon and others believe that the death of Ginsburg, an iconic figure among liberals, will boost popular support.

"RBG's death was not the cause of calls for things like adding seats to the Senate and adding seats to the Supreme Court and thinking about trying to change the electoral college," Fallon said, "but I do think it will cause support for them to grow exponentially."

But other Democrats, including Obama's former White House chief of staff, are ardently opposed to allowing the debate to intrude on a campaign that Biden, according to nearly every public poll, leads with six weeks until Election Day.

Rahm Emanuel, in an interview Monday night, warned Democrats against focusing on "hypothetical" ideas like expanding the court or imposing term limits on its justices, especially if those conversations risk overshadowing imminent threats to abortion rights and the ACA.

His advice: "Just don't talk about it."

Emanuel also said he questions McConnell and the GOP's political calculus.

"I think the Republicans, McConnell and Trump especially, are playing with fire," Emanuel said, a phrase Rep. Alexandria Ocasio-Cortez used on Sunday night during a news conference with Schumer in New York. "Not only are they making a lifetime decision that people don't think should be rushed, from a political standpoint, you're guaranteeing that health care will be at the center of every election going forward."

Any diversion from that message, he said, specifically one focused on health care -- a winner for the party in 2018 -- would be a political gift to Republicans.

"I don't want to get in the way of their self-destruction," Emanuel said.

'A completely different landscape'

Trump and McConnell's rush to fill Ginsburg's seat has prompted many liberals to conclude that the time has come to meet Republican fire with their own. Indivisible, the liberal organization formed after Trump won the presidency in 2016, marshaled the anger of its local groups over the weekend, as the scope of the fights to come came into focus.

"The main thing we need to do is win in November, and then as soon as Democrats take control of the Senate, they really need to start governing immediately to undo the damage that Trump has done," said Meagan Hatcher-Mays, director of democracy policy for the Indivisible Project. "That changed almost overnight, I would say, from Friday to Saturday. It just feels like just a completely different landscape."

For Democrats in the Senate and other leadership positions who have so far been more circumspect in their remarks, Hatcher-Mays said, the harsh realities might not fully land until, and if, Biden wins the election and the party gains a narrow Senate majority -- only to see their priorities blocked by a Republican minority.

"A lot of Senate Democrats, even middle-of-the-road Senate Democrats, are not going to want to sit back and watch Joe Biden's entire agenda be thwarted by one person, one Republican in the Senate," she said. "I think the reality of the situation is going to hit pretty quickly."

Obama's declaration did not immediately let loose a floodgate of converts, but his standing offered a sense of political legitimacy to the movement. Asked first if he would support adding justices to the Supreme Court, then about getting rid of the filibuster, Schumer on Sunday night delivered the same message he gave to his caucus during a call the day before.

"We first have to win the majority, because if we don't win the majority, these questions are all moot," Schumer said, when asked about the filibuster. "But if we win the majority, everything is on the table."

Others in his caucus have been less cautious.

Massachusetts Sen. Ed Markey, who recently fended off a tough primary challenge with strong progressive backing, came out of the gates on Saturday calling for Democrats to use the threat of such radical action as a deterrent against Republicans' Supreme Court plans.

"Mitch McConnell won't back down, and neither will we. We can defeat him if we mobilize and organize," Markey tweeted. "That is why we must make it absolutely clear that if McConnell attempts to fill this seat, we will abolish the filibuster and expand the court when we retake the Senate."

Hawaii Sen. Brian Schatz has suggested that Republicans might leave the Democratic caucus no other option.

"It is going to be very hard after the procedural violence that Mitch McConnell has inflicted on the Senate and the country for anyone to justify us playing it soft next year just to satisfy pundits," Schatz tweeted. "We must use the power that voters give us to deliver the change we are promising."

A messaging question

Democrats' next steps will be heavily influenced by the outcome of the unfolding clash over Ginsburg's seat. If McConnell fills it before the election or, perhaps even more divisively, after Trump and Senate Republicans potentially lose in November, intra-party dynamics could shift even further.

Sean McElwee, co-founder and executive director of the progressive group Data for Progress, called the threat of eliminating the filibuster, adding justices to the court and new seats in the Senate, the Democratic Senate minority's "only credible threat."

"You need a number of Democratic senators to be sending that message to McConnell, because it's really the only point of leverage that Democrats have," McElwee said. "Most of the procedural stuff that I'm seeing come out there is a bit of a fantasy, to be entirely frank."

But he also acknowledged that it would be difficult -- and perhaps counterproductive -- for some Democrats, especially those running difficult races in traditionally red states, to weigh in too heavily on issues that still divide opinion, or are only slight above water in popularity, with most voters.

"It seems, to me, to be totally acceptable for Markey to be messaging this in a different way than Cal Cunningham is (in North Carolina), which is different than the way that Barbara Bollier is (in Kansas)," McElwee said, referring to a pair of Democrats vying to unseat Senate Republicans. "They represent and seek to represent different swaths of the American population. We shouldn't fall into the trap of believing that every message is for everyone."

Andrew Yang, a 2020 presidential candidate who has advocated for Supreme Court term limits, chalked up Biden's hesitance to his personal history with the institution.

"Joe has a different vantage point because he spent so long in the Senate," said Yang, a CNN contributor who ran against Biden in the primary. "He is someone who has a healthy respect for a degree of institutional continuity."

But in a year that has been marked by disruption and with the political order that Biden once knew largely toppled, the calculus guiding his campaign could, even in victory, change by the time he takes office.

"We are facing simultaneous crises, one on top of another, and many Americans are justly concerned that our government and institutions are not up to the challenges that are facing us," Yang said. "In that situation, new things become necessary and popular because we can see that our current approaches are not working."