It has become an annual harbinger of autumn in this era of divided government: The calendar swings from August to September, Congress returns from its long summer break, and Republican leaders try to figure out how to keep the federal lights on past the end of the month.

In 2013, John Boehner gave in to Senator Ted Cruz and his conservative allies in the House, and the government shut down for two weeks in a failed fight over Obamacare. A year ago, Boehner and Mitch McConnell succeeded in twice putting off a losing battle over immigration until after they could wrest control of the Senate from the Democrats.

With federal funding set to expire on September 30, conservatives are once again demanding a standoff that Boehner and McConnell are hell-bent on avoiding. This time around, the issue that might prevent an orderly—if temporary—extension of funding is Planned Parenthood. Along with Cruz, House conservatives insist that any spending bill sent to President Obama’s desk explicitly prohibit taxpayer dollars from going to the women’s health organization, which has come under fire over undercover videos that purportedly show its officials discussing the sale of fetal tissue. Democrats have rallied around Planned Parenthood, and an effort to ax its approximately $500 million in annual funding is likely to fall short, either by running into a filibuster in the Senate or a presidential veto.

So what makes this fight any different? For starters, conservatives who once acknowledged the futility of the 2013 shutdown have become emboldened by the anti-establishment fervor sweeping the Republican presidential race, where political novices Donald Trump, Ben Carson, and Carly Fiorina are all surging in the polls. And second, these same members are now openly threatening a revolt against Boehner through a rarely-used procedural maneuver that could—conceivably—oust him from power.

The latter idea was the brainchild of Representative Mark Meadows, a second-term Republican from North Carolina, and it began in July on something of a lark. Shortly before the August recess, Meadows introduced what’s known as a “motion to vacate the chair.” If successful, it would trigger the election of a new speaker. Republican leaders briefly considered calling a vote on the measure to prove Boehner retained enough support to remain in office. Yet Meadows—or any other member—has the power to force a floor vote within 48 hours through the introduction of a “privileged resolution.” Such a move hasn’t worked in the House in 105 years, but after initially dismissing Meadows’s move as poorly-timed and somewhat bizarre, his allies now see it as something else: leverage.

Representative Mark Meadows (J. Scott Applewhite / AP)

“I was originally against Mark’s doing what he did,” Representative Mick Mulvaney, a South Carolina conservative, told me by phone. But after hearing from angry constituents in August, he said he’s come around. “Now folks know that the issue of a vote of no confidence is on the table and that if the leadership doesn’t change its course, then it’s sort of hanging over their head like a sword of Damocles.”

For Republicans like Mulvaney, the rise of Trump and the strength of other anti-establishment candidates like Carson, Fiorina, and, Cruz is proof that GOP leaders like Boehner and McConnell have been vastly underestimating the party’s grassroots. What Boehner and McConnell like to dismiss as the fringe, in other words, is actually the majority.

Anti-abortion conservatives view the defunding of Planned Parenthood as a no-brainer, both substantively and politically. “This is so wrong that there is no way we can allow taxpayer money to continue to go to this organization,” said Representative Jim Jordan, who leads a newly formed group called the House Freedom Caucus. Like Mulvaney, he rejected the idea that conservatives were pushing the GOP down the same perilous road seen in 2013. “This is a completely different dynamic here," he argued. “You’ve got an organization on video advocating and engaged in activity that everyone knows is wrong and that appears to be criminal.”

There’s no question the videos have been damaging to the organization, and there’s little dispute among Republicans that it shouldn’t receive government support, especially when the money could simply be shifted to other women’s health groups that are less contentious. But as has been the norm for Republicans in recent years, a debate over tactics has taken on outsized significance. “Our leadership has probably one chance left to save the party, and it’s on Planned Parenthood,” Mulvaney told me. “And if they don’t, if they put up a show vote, or if they sort of say they’re going to fight but then don’t because they knew that’s what they’re going to do anyway, then the party is done, and Donald Trump will be our nominee, and it will redefine what it means to be a Republican. I don’t know if they get it.”

A Boehner spokesman said no decisions on the spending bill, known as a continuing resolution, would be made until lawmakers return to Washington next week. McConnell has been more blunt. Since taking over in January, the Senate majority leader has been in the business of managing expectations while Obama remains in office. He’s sworn off another shutdown, and on Tuesday he conceded that the conservatives’ Planned Parenthood strategy is destined to fail. “We just don’t have the votes to get the outcome that we’d like,” McConnell told WYMT in Kentucky.

I would remind all of your viewers: The way you make a law in this country, the Congress has to pass it and the president has to sign it. The president has made it very clear he’s not going to sign any bill that includes defunding of Planned Parenthood, so that’s another issue that awaits a new president hopefully with a different point of view about Planned Parenthood.

To many Republicans, that’s just an honest assessment of the political reality. To conservatives like Cruz, Mulvaney, and Jordan, it’s defeatist. Cruz, who accused McConnell of lying to Republicans earlier in the summer, has already vowed an aggressive fight to defund Planned Parenthood in December. And how many of the other 16 Republican presidential candidates join his call could determine the level of outside pressure McConnell and Boehner will face. McConnell, however, has a firmer hold on his position than Boehner, who lost a record 25 Republican votes when he was reelected as speaker in January and has shown a tendency to underestimate the level of opposition within his conference.

Would Meadows actually pull the trigger and force a vote to try to remove Boehner? He was vague during an interview on Tuesday, saying that his resolution was designed to prod the leadership into including more conservative voices in its decision-making and agreeing to other process reforms. “For me it’s more about changing the way that we do business as opposed to changing the actual person,” Meadows told me. “A lot of it will depend on what happens during the month of September and maybe the few weeks that follow that.” Meadows, who was briefly stripped of a subcommittee chairmanship for voting against the leadership, has criticized a “culture of punishment” in the House GOP, but he said his effort was not aimed at retribution for himself. The Planned Parenthood fight, he said, would be “a huge factor” but not “a litmus test” in his decision.

Boehner’s allies have scoffed at Meadows’s maneuver, in large part because neither he nor any of his conservative colleagues have put forward a plan—or an alternative Republican candidate—if the speaker is actually deposed (which remains an unlikely scenario). Representative Tom Cole of Oklahoma likened it to “blackmail” and said it was “a very reckless strategy” that could empower Nancy Pelosi and the Democrats. “If they want to bring it up, bring it up,” Cole said. “I’m tired of people threatening members of their own team. What’s wrong here is Republicans treating other Republicans like they’re the enemy.”

On Planned Parenthood, Cole said he strongly supported defunding the group, but not if it led to a government shutdown. “Just because you want to do something doesn’t mean you actually have the political power to accomplish it,” he said. “Go win some elections. I think we’re always inclined to reach beyond what we can do. You get a different president, we’ll take care of Planned Parenthood. But having a fight this fall that you can’t win? That strikes me as unrealistic.”

Whether victory is realistic or not, the question of when and how far to fight has divided Republicans for four years. And as the debate over Planned Parenthood and government funding will soon show, that battle rages on, as strong as ever.