WASHINGTON – Summoning memories of his slain brother, Sen. Edward M. Kennedy led two generations of the First Family of Democratic politics Monday in endorsing Barack Obama for the White House, declaring, “I feel change is in the air.”

Obama is a man of rare “grit and grace,” Kennedy said in remarks salted with scarcely veiled criticism of the Illinois senator’s chief rival for the presidential nomination, Sen. Hillary Rodham Clinton, as well as her husband, the former president.

“Today isn’t just about politics for me. It’s personal,” Obama told a boisterous crowd packed into the American University basketball arena.

A liberal lion in his fifth decade in the Senate, the Massachusetts senator is in a position to help Obama court voting groups who so far have tilted Clinton’s way. These include Hispanics, rank-and-file union workers and lower-income, older voters.

“With Barack Obama we will close the book on the old politics of race against race, gender against gender, ethnic group against ethnic group, and straight against gay,” Kennedy said.

“There was another time, when another young candidate was running for president and challenging America to cross a new frontier. He faced criticism from the preceding Democratic president, who was widely respected in the party,” Kennedy said, referring to Harry S. Truman.

“And John Kennedy replied, ‘The world is changing. The old ways will not do. … It is time for a new generation of leadership.’

“So it is with Barack Obama,” he added.