on someone's side

Idioms  

1. In support of someone's views or interests, as in I'm glad you're on my side in this debate, or With the Canadians on our side, we should be able to persuade the Mexicans of a North American policy. [1300s]

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Example Sentences

When he is on someone’s side, there is no more relentless ally.

From New York Times

I sort of supported her, but at the same time, it was all up to Stephen, so it was hard to be on someone’s side.

From Time

In the townships, they were seen as neutrals, when a black photographer would have been assumed to be on someone's side -- the ANC or the Zulus -- and at night they went home to drink in upscale bars and sleep in comfortable suburbs.

From Salon