U.S. Sen. Elizabeth Warren (D-MA) (R) talks to Secretary of State and former U.S. Sen. John Kerry (D-MA) (L) during a re-enactment of the swearing-in for U.S. Senator William 'Mo' Cowan (D-MA) February 7, 2013 at the Old Senate Chamber of the U.S. Capitol in Washington, DC. Cowan was appointed by Massachusetts Governor Deval Patrick as interim U.S. Senator to fill the seat that left vacant by Secretary of State and former U.S. Sen. John Kerry.