A year after the U.S. Supreme Court gutted a key anti-discrimination provision of the Voting Rights Act, a congressional push to undo the justices’ ruling is stalled because of opposition from Republicans, Sen. Patrick Leahy, D-Vt., said Wednesday on Capitol Hill.

The Senate Judiciary Committee held a hearing Wednesday on the Voting Rights Amendment Act, introduced six months ago by a bipartisan group of lawmakers in response to the 5-4 high court decision in Shelby County v. Holder.