US Democratic presidential candidate Senator Hillary Clinton (D-NY) speaks at the National Building Museum in Washington June 7, 2008. Seated at right are her daughter, Chelsea and husband, former US President Bill Clinton (2nd R). Clinton endorsed presumptive Democratic presidential nominee Senator Barack Obama (D-IL) to be the Democratic U.S. presidential candidate on Saturday and suspended her own White House bid less than a week after the Illinois senator secured enough support to win the nomination. Clinton's endorsement of Obama in a speech at the National Building Museum marked the beginning of efforts to reunite the Democratic Party after a long and divisive campaign battle that ended on Tuesday when Obama won the support of enough delegates to clinch the nomination. REUTERS/ (UNITED STATES) US PRESIDENTIAL ELECTION CAMPAIGN 2008 (USA)