One of the most important legislative drives this fall will manifest John A. Boehner’s promise to “clean the barn” for the next speaker — or else looms as the first ideological comeuppance for the new Republican leadership.

In recent days, the suspense has changed from “if” to “when” Congress will reopen the Export-Import Bank, effectively padlocked since this summer thanks to one of the most consequential current disputes between the GOP’s small-government purists and its big-business buddies.

The dynamic of that tussle has been transformed by the changing of the guard within the House Republican high command.

While Boehner was trying to hold on in the top chair, he was reluctant to pick yet another public fight with his right flank. He (and, in the recent past, a majority of his majority) have outwardly supported the work of the Ex-Im Bank, which helps American businesses sell their products abroad by providing loans and loan guarantees as incentives to foreign customers. But tea party conservatives have been much more vocally passionate in lambasting the agency, which they see as wrongly putting taxpayer dollars at risk in a form of corporate welfare amounting to crony capitalism.

The Ohioan’s impending departure is giving a pivotal bloc of like-minded members from the GOP’s Chamber of Commerce wing an opening for a move generally considered bold to the point of political recklessness — but which they’re confident will prove entirely safe during a leadership vacuum.

At least three dozen Republicans say they’re ready to support a “discharge petition,” a rarely successful form of parliamentary guerrilla warfare that aims to force a floor vote on legislation stalled in committee or blocked by the leadership.

With the Obama administration praising the bank as a key aid to boosting global competitiveness, almost all the Democrats will sign that document as soon they watch a decent number from the GOP go first, producing a House majority publicly committed to reviving the Ex-Im’s charter for another four years.

Since 64 senators (22 of them Republicans) voted for just such a reauthorization this summer, victory looks mathematically assured if the House moves such a measure.

The question looks to be whether the bank gets granted its renewed lease on life quickly and quietly in the next few weeks, or belatedly and grudgingly near the end of the year.

At their weekly closed-door caucus, House Republicans spent almost half an hour Wednesday in a testy but inconclusive debate about the discharge petition and the future of the bank, which almost all those hoping to advance in the leadership want to kill. Afterward, Boehner urged the Financial Services Committee to move legislation (which has been bottled-up by Chairman Jeb Hensarling, R-Texas) before having their job done for them by the petition signers.

If that request goes unheeded, Boehner has signaled a willingness to force the issue, thereby bolstering his legislative legacy and short-circuiting any resistance from the next leadership team. He could do that by openly embracing the discharge petition. Or he could arrange for language reviving the bank, which hasn’t been authorized to start new business since July, to be added as an amendment to some upcoming bill. (For example, to avoid a suspension in federal public works spending a stopgap highway bill must pass by Oct. 29, the penultimate day of Boehner’s career and the day the new speaker is scheduled to be chosen by the whole House.)

If Boehner doesn’t act, the new leaders may want to show they can hold the line against the bank for as long as possible.

California’s Kevin McCarthy used to be a supporter of the bank but switched sides just as he got elected majority leader 15 months ago. His rivals for speaker, Jason Chaffetz of Utah and Daniel Webster of Florida, both voted to kill the agency when the House last voted on a reauthorization, three years ago.

So did both candidates for majority leader, GOP Whip Steve Scalise of Louisiana and Tom Price of Georgia, and whip candidates Patrick T. McHenry of North Carolina and Dennis A. Ross of Florida. The only Ex-Im ally bidding for leadership is Rules Chairman Pete Sessions of Texas, who’s vying for whip.

The discharge petition system is designed to be as procedurally cumbersome as it is politically dicey, which is why it’s been 13 years since such an effort succeeded. (That was how the last big campaign finance law got enacted.)

Tennessee’s Stephen Fincher has filed the initial paperwork and is now gathering signatures. Assuming he unveils the necessary 218 supporters in the coming days — which is a sure thing, he said Wednesday — he could still be forced to wait until after next week’s recess for his proposal is added to the House calendar. Then, since motions to consider discharge petitions are in order only the second and fourth Mondays of the month, the Ex-Im’s friends have an outside chance to get their way on Oct. 26.

McCarthy has been urging fellow Republicans to keep their signatures to themselves, but he does not yet have the title (and the attendant muscle) to enforce one of the few remaining bedrocks of party discipline: You can publicly deride the speaker’s strategies, vote against a speaker’s wishes on legislation and even oppose his election to the top job — but you may not seek to usurp the speaker’s fundamental prerogative to set the House’s agenda.

During the government shutdown two years ago, not a single Republican signed a Democratic petition designed to end the budget impasse without condition. And during the 2014 campaign, no Republicans signed Democratic petitions to force votes on a minimum wage increase and an immigration overhaul. Such an abandonment of loyalty to Boehner was seen as bridge too far for even the most electorally imperiled, or ideologically centrist, GOP member.

That’s not going to be the case while he’s heading toward the exits without his replacement firmly installed. What to watch for is whether a bloom of support for export financing — of all things! — ends up fracturing or oddly unifying the Boehner-free team.

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