Senate Democrats sparred with Postmaster General David Steiner on Wednesday over the U.S. Postal Service’s move to stop delivering mail-in ballots in states that don’t hand over their voter rolls to the federal government.

Steiner, who has stayed out of the political spotlight since taking the lead role at USPS last year, was grilled by Democrats about the entity’s decision to follow President Donald Trump‘s executive order, functionally establishing a national voter verification system for mail-in ballots. In late May, USPS proposed a rule that would create a “Mail-In and Absentee Participation List” in line with Trump’s executive order request, if approved.