Sorry if this has been asked before but why didn’t Dorne withdraw it’s support for the crown when Rhaegar kidnapped Lyanna? It was a monumental insult to Elia, and Doran must have known that Aerys was (slowly going) mad. Was there just too much history and too many loose ends for a Dornish-rebel alliance to ever work?

A couple reasons. Firstly, Aerys was holding Elia as a hostage, so Doran withdrawing his support for the crown means his sister dies. Secondly, regardless of any insult, Rhaegar is still the crown prince and Aegon, Doran’s nephew, is his heir. Doran’s going to fight for his nephew’s rights even if he thinks his brother-in-law is an adulterous asshole.