U.S. Postmaster General David Steiner defended a controversial proposal backed by US President Donald Trump that would require states to provide lists of voters who received mail ballots. Testifying before the Senate Homeland Security and Governmental Affairs Committee, Steiner said the U.S. Postal Service could refuse to deliver ballots in states that do not comply with the requirement.

Postmaster General David Steiner says the USPS won’t deliver ballots if states don’t hand over their voter lists to Trump.

David Steiner, who has largely stayed out of the political spotlight since taking the lead role at USPS last year, was grilled by Democrats over mail-in voting.