Seven Supreme Court justices ruled that federal law prevents Arizona from requiring a proof of citizenship from newly-registering voters, but Sen. Ted Cruz, R-Texas, hopes to change that during the ongoing debate over the Senate immigration bill.

“Today #SCOTUS ruled federal ‘Motor Voter’ law preempts [Arizona's] proof-of-citizenship requirement for voter registration,” Cruz tweeted. “I’ll file amendment to [the Gang of Eight's] immigration bill that permits states to require ID before registering voters & close this hole in fed[eral] statutory law.”

Justice Antonin Scalia, in the majority opinion, wrote that the Motor Voter law “precludes Arizona from requiring a federal form applicant to submit information beyond that required by the form itself.”

Justice Clarence Thomas, who was joined in his dissent by Justice Samuel Alito, countered that states have the constitutional authority to “determine the qualifications of voters in federal elections, which necessarily includes the related power to determine whether those qualifications are satisfied,” according to the Associated Press.