Watch out, mid-to-upper septuagenarians. Newly minted GOP presidential candidate Nikki Haley has questions about your mental acuity! The South Carolina governor and former U.N. ambassador formally launched her campaign Wednesday with, among other things, a call for “mandatory mental competency tests for politicians over 75 years old.” That line was surely aimed at pleasing Republicans who’ve convinced themselves that 80-year-old President Joe Biden is senile (while also being a devious criminal and an all-powerful leftist singlehandedly transforming America into a socialist hellscape). But it was also a shot at 76-year-old former President Donald Trump, also a candidate, and at a...