A judge in Massachusetts has stopped President Trump's attempt to change how U.S. elections work. The judge agreed with a group of Democratic state lawyers who said Trump's changes were against the Constitution. Trump's order, given in March, wanted people to show proof of citizenship to register to vote. It also aimed to count only mailed ballots that arrived by Election Day and to give federal money for elections only if states followed this new rule. The White House said the order would make sure elections were "free, fair, and honest." However, Judge Denise J. Casper decided that the states would probably win their legal cases. She explained that the Constitution does not give the President special power over elections. The ruling also stopped the part of the order that required states to reject any mail-in or absentee ballots received after Election Day. This is the second time a judge has blocked parts of Trump's election order; a judge in Washington D.C. had already done this.