LOS ANGELES (Reuters) - A federal judge on Wednesday ruled that absentee ballots in the presidential battleground state of North Carolina must have a witness signature, a boost for Republican groups seeking to enforce stricter rules on mail-in voting. U.S. District Judge William Osteen in Greensboro issued an injunction essentially barring voters from being able to “fix” an absentee ballot they had already sent in if it lacked a third-party signature attesting that the voter, and not somebody else, signed the ballot. The judge was reversing a previous directive by state officials that had allowed voters to remedy the lack...