...prove they are U.S. citizens were upheld by a federal judge on Wednesday, potentially opening the door for more states to enact such measures. The two Republican-led states had sued the U.S. Election Assistance Commission, set up by Congress after chronic voting problems during the 2000 presidential election, saying the agency wrongly prevented them from demanding such documentation in voter registration forms in the state. Laws passed in the two states requiring proof of citizenship for voters are...