Republican Rob Astorino is going nuclear in his effort to oust heavily favored Democratic incumbent Andrew Cuomo in the race for governor. Astorino claims in a provocative new TV spot—his own take on the infamous “daisy girl” attack ad that helped Lyndon Johnson trounce Barry Goldwater in the 1964 presidential election—that Cuomo could wind up in prison because of a federal criminal probe targeting a “cloud of corruption” hovering over the governor’s office. The original 60-second “daisy” ad, which ran at the height of the Cold War amid rabid fear of Soviet-US nuclear combat, featured a little girl in a...