(ONN) – The Supreme Court of Ohio has struck down the state’s newly-drawn Congressional district map, saying Republicans violated the Ohio Constitution by drawing districts that overwhelmingly favored GOP candidates.

The decision comes just days after the high court made a similar ruling concerning the map of the state’s House and Senate districts.

Ohio Supreme Court Justice Maureen O’Connor was again a key vote in the 4-to-3 decision to reject the map, which would have given Republicans a 12-to-3 district advantage in a state that only leans Republican.

Ohio lawmakers will be sent back to the drawing board to craft a new map within 30 days.

If they can’t find a solution, the Ohio Redistricting Commission will have 30 days to do so.