The Republican-led US House of Representatives passed a bill Thursday that would add proof-of-citizenship requirements to voter registration, in a vote designed to mobilize supporters concerned about election security that has little chance of becoming law.

Led by Republican Chip Roy of Austin, the Safeguard American Voter Eligibility Act – known as the SAVE Act – would mandate that voters present certain documentation to vote, including ID cards consistent with REAL ID requirements. The bill passed 220-208, with four Democrats joining all voting Republicans in favor of the bill.

Voting rights advocates have argued the bill will make it harder for millions of Americans to register to vote.