I think it's the same regret that most of the smart cons have. They're grifters who kept lying and lying to continue their grift, but the eventual outcome was a demented narcissist in office who went out of control and disrupted many of the grifts they were doing in the first place.
They wanted just another smart grifter in office, but years of convincing the dumbest parts of the US voting electorate led to a Frankenstein's monster.