The governor’s exit from the race should be a chilling reminder to the other contenders of just what they’re getting themselves into when they head to the CNN debate stage next week. Perry was an A-list candidate back in 2012, snatching Michele Bachmann’s momentum from her Iowa Straw Poll win and drawing crowds. This time four years ago, he was leading the polls in the race for the 2012 GOP nomination.

But his one debate gaffe—when he couldn’t name the third federal agency he wanted to eliminate—ended that effort. The damage lasted; Perry’s “whoops” flub came up in virtually all the coverage of his 2016 bid, and became the defining moment of his political career.

Which, some will convincingly argue, is unfair.