The U.S. Supreme Court delivered a victory Monday to voting rights advocates who have been fighting a number of recent state laws they say make it more difficult to vote.
Justices struck down an Arizona law requiring voters show proof of citizenship to register.
The decision protects what's known as the motor voter law and it keeps states from adding requirements to a federal registration form.
The 1993 voter registration act requires individuals to promise in writing that they are citizens but Arizona wanted more.
Arizona lawmakers passed a law requiring proof of citizenship, for instance a birth certificate, from anyone using the federal form.
On Monday justices ruled that the Arizona law went too far.
"90 percent of the people's whose applications were rejected because they didn't have proof of citizenship were U.S. citizens ," said Laura Murphy of the American Civil Liberties Union.
The 7-2 decision striking down the Arizona law- impacts four other states with similar requirements, Alabama Georgia, Kansas and Tennessee as well as at least 12 others considering similar legislation.
"What's so important about this ruling is it is saying to all these other states you can't come up with all these restrictions that make it harder for voters to vote," said Barbara Arnwine, of Lawyers' Committee for Civil rights under law.