The bar for a chief executive of a public corporation to repudiate a United States president is extraordinarily high. Corporate leaders aren’t given their power, prestige, responsibility and nine-figure pay packages to use the corner office as their personal soapbox.

With President Trump’s comments on white supremacists and other right-wing extremists ringing in the ears of America’s chief executives, that high bar appears to have been passed.

This week, what had been a trickle of defections from the White House business advisory councils over issues like immigration and climate change turned into a torrent. By Wednesday, both of the councils had collapsed; Mr. Trump insisted that he had decided to disband them.

Such a public schism between a president and a business leadership long considered the backbone of the Republican establishment left corporate historians at a loss for precedent. “There’s never been anything to compare to this,” said Jeffrey A. Sonnenfeld, a dean of leadership studies at the Yale School of Management and the author of “Firing Back: How Great Leaders Rebound From Career Disasters.”