Depending on how you reckon some ambiguous cases, SCOTUS has applied the 'principle' somewhere in the ballpark of 17 to 20 times since Purcell itself twenty years ago. Of those, 15 to 17 (again depending on how you count a few deadlock cases w/ no majority) were wins for Republicans over Dems. 85%+
Andy Craig
The upshot of recent developments is that the Purcell principle “seems like it’s really not a principle at all,” says @justinlevitt.bsky.social . “It seems the Supreme Court is picking winners and losers, not doing law.