cast (one's) lot with (someone or something)
To join and steadfastly support another person or group. As soon as news of the CEO's scandal becomes public, I doubt that big investor will want to cast her lot with us. Don't worry, mom—I really don't care about casting my lot with the cool kids at school.
cast one's lot with
Also, cast or throw in one's lot with . Join or side with, no matter what the outcome, as in Bill cast his lot with the new company. [First half of 1500s]
cast (one's) lot with
To join or side with for better or worse.