spear carrier

noun3

1. •
   A person in a play or movie with a minimal part; an extra.

   • [A]ctors would get annual raises through 2008, when even the lowliest spear carrier will make more than $1,500 a week for being on Broadway. — 2004
2. •
   One who serves in a subordinate or menial role.

   • Britain is now widely dismissed—more often in sorrow than in anger—as just an American spear-carrier without any real force of its own. — 2010
3. •
   One who plays a leading or substantial role as a supporter, proponent, etc. representing a group, cause, or point of view.

   • Reed was the preternaturally boyish spear carrier for the religious right, the brash Evangelical who transformed the Christian Coalition into a populist power center. — 2006