Arizona governor signs law requiring proof of citizenship to vote for president

Voting rights advocates say 200,000 people could be affected by measure, which legislature's own lawyers call unconstitutional

Arizona's Republican governor on Wednesday signed a bill requiring voters to prove their citizenship to vote in a presidential election, drawing fierce opposition from voting rights advocates who say it risks affecting 200,000 people.

The bill also requires anyone newly registering to vote to provide proof of their address.