The filibuster took another small-but-significant step last week toward what some experts believe is its inevitable demise. President Biden, in a CNN town hall, expressed an openness to getting rid of it for narrow issues — specifically the debt ceiling and voting rights.

The evidence is pretty clear that the anti-filibuster forces are increasingly winning the argument within the Democratic Party. More and more, the question seems to be when the filibuster will be significantly scaled back or eliminated — and who will be in charge when it happens.

The comments from Biden were significant, because, as a presidential candidate in 2020, he rejected the idea of nixing the filibuster. Then earlier this year, he began talking about reforming it to make it more difficult for the would-be filibusterers. Then a few weeks ago, he floated eliminating it for the debt ceiling. Now he’s talking about doing it for a specific issue area — voting rights, on which Republicans blocked Democrats’ bill last week — that could logically presage a rather swift further rolling-back of the filibuster.

Not that the filibuster is going anywhere imminently. After all, it’s hardly up to Biden. Senate Democrats would need all 50 of their votes to make it happen, and a significant number of Democratic senators (beyond just Joe Manchin III and Kyrsten Sinema) aren’t on board.

But the idea of a narrower carve-out is an interesting one. That’s because it could not only theoretically allow Democrats to pass a key bill on something like voting rights, but also because it might very logically hasten the filibuster’s overall demise. After all, once one side or another nixes the filibuster for an issue they deem to be that important, what’s to stop the other side (or future Senates from the same side) from offering the same justification?

There are and have been significant carve-outs to the 60-vote threshold, as the Brookings Institution’s Molly E. Reynolds detailed in her 2017 book, “Exceptions to the Rule.” (For a good rundown on what they are, see here.)

These include the limited instances in which bills can be passed via reconciliation, as Democrats are attempting to do with their infrastructure/spending bill and as Republicans did with their tax-cut package (and attempted to do with their Obamacare replacement) during the Donald Trump administration. The threshold was also lowered to majority votes in 2013 for non-Supreme Court judicial and executive-branch nominees (by Democrats) and then in 2017 for Supreme Court nominees (by Republicans). In each case, the stated reason was obstruction by the minority party.

But even as those were significant events in the progression and potential elimination of the filibuster, one could make an argument that getting rid of it for nominees wasn’t that drastic — especially given that they involved filling out a government in ways that didn’t used to be so contentious.

One could also seemingly make such an argument about eliminating the filibuster for the debt ceiling, given that it basically amounts to Congress agreeing that the U.S. government should merely pay the bills it has already racked up. Even Senate Minority Leader Mitch McConnell (R-Ky.) once proposed letting a president unilaterally raise the debt limit, with Congress being allowed to vote its disapproval.

Doing this kind of thing for a specific legislative issue area would change things significantly, leading to questions about why this thing would be exempt but that thing wouldn’t.

Advocates of this approach have sought to build into their argument the idea that this wouldn’t necessarily be the case. They argue that voting rights could be carved out not necessarily because they are deemed to be important, but because they are a constitutional issue.

“We allow a simple majority in the Senate to advance legislation during budget reconciliation to protect the country’s financial security,” House Majority Whip James E. Clyburn (D-S.C.) and Rep. Mondaire Jones (D-N.Y.) wrote in a July op-ed, citing the 1974 law that provided for expedited consideration of such things. “We ought to make the same exception when people’s constitutional rights are in question.”

A logical question from there is whether other such issues that could be construed as constitutional might suddenly be exempt. Could Republicans then pass laws restricting abortion rights, for instance, with just a majority vote? Clyburn has indicated abortion rights would indeed meet this test.

But even aside from what other issues this might immediately ensnare, there’s the fact that it would be a big ratcheting-up of filibuster rollback. Democrats effectively argue that voting rights are this significant, so what happens when other issues are deemed to be of such import. Rolling back the filibuster rules in a significant way for the third time in a decade would also speak volumes about the direction in which this is heading.

Another effect that I have referenced and I don’t think has gotten enough attention is the impact of merely talking about such things — and getting some buy-in from the likes of Biden. Even if Democrats aren’t ultimately able to actually roll back that filibuster, it suggests they would be more likely to do so if they get more than 50 votes. It could also instill a belief in Republicans that Democrats are likely to do this eventually, meaning they might as well just nix the filibuster themselves when it’s necessary and convenient.

It’s this progression that some filibuster experts have long pointed to as the most likely path for the demise of the rule — not one swift action, but rather a series of smaller ones.

“We will see more and more attempts to whittle it down through carveouts and exceptions, since senators don’t seem to be able to find a majority for outright abolition,” the University of Miami’s Gregory Koger recently said. “So when the filibuster ends, it will be through a thousand cuts.”

Reynolds agreed that the concept of increasing exemptions pointed in one direction.

“I do think that each targeted application of majority cloture hastens the full abolition of the filibuster,” she told me, “but I also think that we are on the road to full abolition anyway, and the real question is how quickly we get there.”

But Reynolds said it might not necessarily be swift, because that depends on who is in charge, how many votes they have (including whether they have the presidency and the House), and what issues are in play.

“When thinking about whether the filibuster will be eliminated, I generally ask myself this question: Is there something that the majority party cares enough about and is sufficiently united on that it is willing to change the rules to make it happen?” she said. “I think the reason we haven’t see the full abolition of the filibuster yet, or even additional targeted applications of majority cloture, is because nothing has risen to that point yet for either party.”

The GOP’s rejection of the Democrats’ voting rights package seems to have changed the calculus at least somewhat for one very influential Democrat. The White House has said Biden will propose some more concrete filibuster changes in the coming weeks. And the extent to which they include the carve-outs Biden has floated will say a lot about the filibuster’s long-term prognosis.