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.
See also: cast, lot
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.

cast (one's) lot with

To join or side with for better or worse.
See also: cast, lot
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.
See also: