FriedRiceNSpice
Captain
Didn't take any violence for Eastern Europe to flip to the US. A vassal can flip outside of direct military struggle if two conditions are fulfilled 1) the suzerain cannot guarantee protection and 2) the prospective suzerain can offer more benefits to the current ruling class than the current suzerain can.It took Qing two invasions to flip Joseon away from Ming. It took Japan one war to flip Korea away from Qing. It took US one war to flip South Korea away from Japan. The only way you can flip a vassal is to win a war with their suzerain. Korea just sides with the victor, you have to earn it not by words or trade but through violent struggle.