standard-bearer
/ˈstændədˌbeərə(r)/noun
1- a soldier who is responsible for carrying the distinctive flag of a unit, regiment, or army旗手, 打旗的兵。
1.1
- a leading figure in a cause or movement旗手, 领导人：
the announcement made her a standard-bearer for gay rights.
那个宣言使她成为争取同性恋者权利运动的领导人。