cast lot with
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.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
cast (one's) lot with
To join or side with for better or worse.
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.