Obama to pick up another superdelegate

WASHINGTON (CNN) - Barack Obama will be endorsed Tuesday by Kentucky Rep. Ben Chandler, one of the party's superdelegates, three weeks before voters from his state head to the polls in the marathon march to the Democratic presidential nomination, an aide to the Illinois senator told CNN.

Chandler, whose district includes the city of Lexington - home of the University of Kentucky - and the state capital, Frankfort, was first elected in February 2004 in a special election to fill the seat of retiring GOP Rep. Ernie Fletcher. Fletcher had defeated Chandler in the gubernatorial race months earlier.

Chandler joins fellow Democratic Rep. John Yarmuth as the second Kentucky superdelegate to endorse Obama. Sen. Hillary Clinton has the backing of three other Kentucky superdelegates, leaving three - including sitting Gov. Steve Beshear - undeclared.

– From CNN Political Editor Mark Preston