Advocate
noun  ad·vo·cate  \ˈad-və-kət, -ˌkāt\
1:  one who pleads the cause of another;  
2: one who defends or maintains a cause or proposal; ​
3: one who supports or promotes the interests of a cause or group.

verb  ad·vo·cate  \ˈad-və-ˌkāt\ 
1: to support or argue for (a cause, policy, etc.);  
​2: to plead in favor of

Thoughtful Designs
​Linked to a Cause