Consider two of the biggest earthquakes to have rocked the political landscape in the meantime.

Outside Washington, Donald Trump stunned the establishment by jumping out to a gravity-defying lead in the Republican presidential race. He’s sustaining his bid in part through the force of his personality. But he’s also found an audience among disaffected working and middle-class voters by railing against a White House he says has been outfoxed by its trading partners. And he’s called the pending deal, which is officially known as the Trans Pacific Partnership, a “disaster.”

Inside Washington, House Republicans’ hard right flank—channeling the animus Trump’s candidacy has stirred up in the base—just ousted Speaker John Boehner for showing insufficient fight in confronting the administration. While the proximate cause was a looming showdown over federal support for Planned Parenthood, the trade deal also pitted Boehner, as a chief cheerleader, against his rightwing fringe. They’ve pilloried the package as “ObamaTrade.” Back in June, they tried to deny the procedural authority the White House sought to finish negotiations, in spite of the party’s traditional support for expanded trade. Boehner’s likely successor, current House Majority Leader Kevin McCarthy (R-Calif.), supported handing the White House that extra negotiating room this summer. In a Monday statement, he said he’d need to review the agreement “to see if it is a strong deal that also reaches the guidelines set out by Congress.”

Taken together, the developments point to an unusually combustible GOP. But that’s just one dynamic complicating prospects for the 12-nation deal, which would forge a new trading regime for 40% of the global economy.

Democrats are arguably divided even more bitterly than Republicans. A strong majority of party members in Congress are under pressure from labor and environmental groups and oppose the president on the issue. The debate is bleeding into the Democratic race for president as well. Hillary Clinton promoted the deal while she served as Obama’s Secretary of State. But after facing a stiffer-than-expected challenge from independent Vermont Sen. Bernie Sanders on her left (who has denounced the deal for what he’s called weak labor and environmental protections), she came out over the summer against handing the president the so-called “trade promotion authority” he needed to guarantee the finished package gets an up-or-down vote on Capitol Hill. While she’s held the deal at arm’s length since, it’s not clear how she’ll come down on the final product.

Meanwhile, if Vice President Joe Biden decides to jump into the race, his day job will likely require him to help sell the agreement.

The calendar guarantees that the debate will remain front and center in the presidential contest. Congress will have 90 days to review the deal before voting on it, setting up the possibility of an early January reckoning, just before the first primary events.

How outside groups line up and weigh in presents yet another variable. Organized labor startled the corporate lobby promoting the deal this spring and early summer with the ferocity of its pushback. Labor unions have treated the package as something akin to an existential threat, and they spared no effort earlier this year to hammer home to Congressional Democrats that they’d harbor a particularly long memory on the vote. The AFL-CIO is expected to reprise the effort.

The way business interests align could prove just as consequential. Pharmaceutical giants are upset that the deal cuts the 12-year monopoly protection they enjoy under U.S. law for their biologic medicines down to a five-to-eight year window—a protest that’s caught the attention of Senate Finance Chairman Orrin Hatch (R-Utah). And tobacco companies object that the deal limits their legal recourse for going after foreign governments that adopt anti-tobacco laws. Such parochial considerations could further splinter the Congressional coalition backing the deal.