President Donald Trump said this week he is preparing an executive order that would prohibit states from using mail-in ballots and certain voting machines ahead of the 2026 midterm elections. He argued—without evidence—that mailed ballots and tabulators are unreliable and claimed the federal government has ultimate authority over how votes are counted. Colorado Secretary of State Jena Griswold, a Democrat, called the plan an attack on state-run elections and vowed to mount a legal challenge. “Mail ballots are the most secure, accessible way to vote,” she said, adding that Trump was “taking cues about democracy from a dictator—Putin.” Colorado has used universal vote-by-mail for nearly a decade. Nevada’s Democratic secretary of state, Cisco Aguilar, separately rejected a pair of Justice Department requests for voter data that followed the president’s March order requiring documentary proof of citizenship to register. Aguilar said the requests conflict with state law and pledged that Nevada would not be “intimidated.” Nearly 670,000 Nevadans—about half the electorate—voted by mail in 2024, including large shares in two counties that favored Trump by more than 30 points. Election-law scholars interviewed by NPR said the Constitution gives Congress, not the White House, authority to regulate federal elections, making unilateral action by the president vulnerable to immediate court challenges. State officials in both Colorado and Nevada said they are coordinating with their attorneys general and expect litigation if the executive order is issued.