The only one who is winning here is Trump — because he just keeps doing it and all he gets is a stern warning from the artists. Even if they sue, it’s not like he will pay them. They could possibly sue the RNC, but without the label or RIAA behind them, it would just be dragged out in court for years.
They really cant sue if he pays the licencing fee but its still bad for Trump when a popular recording artist says "Hey, we think your an asshole too" its just bad press.
Madonna had to show up unannounced to one of their houses and beg to get the green light for the sample in hung up. While I really enjoy the growing list of artists telling trump to kick rocks, ABBA is not at all surprising.