Legislation that would require proof of U.S. citizenship for new voters has become a rallying cry for President Donald Trump. The Senate will take up the bill this week. It would require voters to provide proof of citizenship when they register and to present approved identification when they go to the polls, among other new rules. Federal law already requires that voters in national elections be U.S. citizens. But the legislation would lay out strict new requirements for voters to prove their status. The bill is not expected to pass the Senate because of unified Democratic opposition. But Trump is demanding that Republicans push ahead.