Side with
Definition 1 of 1
Pro Tip 1/3Choose Carefully
Use 'side with' when a choice must be made in an argument. Your choice shows support for one side. 
During the debate, I had to side with Sarah because her arguments were stronger.
Pro Tip 2/3Conflict Implication
'Side with' implies that there's a conflict or disagreement, and you're choosing to support one perspective. 
The jury had to side with the plaintiff due to the overwhelming evidence presented.
Pro Tip 3/3Emotional Weight
Choosing to 'side with' someone can carry emotional weight and affect relationships, so it's often a significant decision. 
She decided to side with her brother, which strained her friendship with his opponent.