Sen. Elizabeth Warren, D-Mass., introduced a bill Wednesday that would posthumously revoke 20 Medals of Honor awarded to U.S. soldiers who slaughtered hundreds of Native Americans -- mostly women and children -- at the Wounded Knee Massacre of 1890. The Remove the Stain Act accompanies a House version introduced earlier this year by Democrats Paul Cook of California, Denny Heck of Washington and Deb Haaland of New Mexico.