WASHINGTON (AP) — President Donald Trump has signed an executive order that aims to tighten voting rules by creating a national list of eligible voters and limiting mail ballots. The order signed Tuesday directs the Department of Homeland Security to work with the Social Security Administration on state-by-state voter lists. It also seeks to stop the Postal Service from sending absentee ballots to people not on approved lists. The order calls for adding barcodes on ballot envelopes and threatens to withhold federal funds from states that do not comply. Democratic election officials in Oregon, Arizona, and Maine quickly promised lawsuits and non-compliance. Legal experts also question the order’s constitutionality.