Rep. Justin Amash, R-Mich., one of the few congressmen who has been labeled “libertarian,” has introduced an amendment to the defense appropriations bill that would defund the National Security Agency.

Amash announced his push to defund the NSA on his Twitter account, writing “Most important bill this week: DoD Approps. We can defund NSA’s unconstitutional spying on Americans — if House leaders allow amendments.”