His order included provisions that would have required people to show documentary proof of citizenship to register to vote and prevented mail ballots from counting if they are received after Election Day.
The ruling on Wednesday by U.S. District Court Judge Denise Casper effectively makes permanent a preliminary order she issued a year ago.
Casper agreed with arguments from Democratic attorneys general who filed the lawsuit that the Constitution gives states and Congress, not the president, the power to regulate elections.
