The decisive victory of former state chief justice Roy Moore, a flamboyantly polarizing culture warrior, in Tuesday’s Alabama Senate primary offers one measure of which vision is ascendant in the party. Senator Luther Strange, the appointed establishment replacement for now-Attorney General Jeff Sessions, drew tenacious support from business and Senate GOP leadership (along with a more tepid endorsement from Trump). Yet Moore’s win demonstrated that the appeal of Trump-style populism is still rising in the GOP. His victory is sure to inspire other anti-establishment candidates to pursue primary races that will sharpen the GOP’s fault lines.

Republicans have usually found ways to balance the contrasting priorities of their country-club and working-class wings since Richard Nixon first attracted large numbers of blue-collar whites half a century ago. But the tension is growing more acute under Trump, because the GOP is now pressing so hard on both fronts.

While previous Republican leaders formulated tax proposals that tilted most of their benefits to their upper-income supporters, rarely has the party tried to revoke benefits from its lower-income supporters as sweepingly as during the serial efforts to repeal the ACA. And while the GOP has tapped racial anxieties before, Trump has made his appeals to white racial resentments far more overtly—from his refusal to immediately condemn Ku Klux Klan leader David Duke during the GOP primaries to his “very fine people” moral equivalency about Charlottesville.

Even under these pressures, the bonds connecting the Republican coalition could still hold. Some Democrats fear that if Republicans pass a big tax cut they will reel back many business leaders and college-educated white voters who have recoiled from Trump. Conversely, some conservative operatives believe Trump can surmount any doubts about his economic allegiance among blue-collar and older whites if he remains their defender against the cultural forces he says are threatening “our culture” and “our history.”

But the past week’s events point toward another possibility: that Trump and the GOP could lose just enough support on each front to leave the party vulnerable.

The widespread backlash last weekend against Trump’s attacks on NFL players protesting police brutality—even from an array of wealthy team owners who had supported his campaign—sent the same message as the earlier exodus of business leaders from his administration’s advisory councils after Charlottesville. Both incidents showed that even business leaders who largely agree with Trump’s economic agenda concluded they could not remain associated with his racial views. That’s either because they were personally offended, or they considered the association politically indefensible given the increasing diversity of their own workforces and customer base.