Famed Harvard Law School professor emeritus Alan Dershowitz, a lifelong Democrat, is officially registering as a Republican. 

Dershowitz argued in an op-ed in the Wall Street Journal on Monday that the Democratic Party has become "the most anti-Israel party in U.S. history." He also said that the hard-left, anti-Israel wing of the party has moved from the fringe to the mainstream. 

"I believe that the Democratic Party’s hostility to Israel represents a deeper and more dangerous shift away from the center and toward a radical approach that is bad for America and the free world. So I intend to work hard to prevent the Democrats from gaining control of the House and Senate," Dershowitz wrote. 

Deshowitz said that he still "strongly" disagrees with Republicans on abortion, separation of church and state, immigration, healthcare and taxes, "among other things."