FILE - In this Aug. 31, 2011, file photo AFL-CIO President Richard Trumka talks to President Barack Obama in the Rose Garden of the White House in Washington after Obama urged Congress to pass a federal highway bill. Labor remains a core Democratic constituency and union leaders will stand with Obama in Detroit this Labor Day, where he will address thousands of rank-and-file members during the city's annual parade. (AP Photo/Evan Vucci, File)