NEW YORK (AP) — Attorney General Eric Holder on Friday urged law school graduates to continue the tradition of modernizing the American legal system.

Delivering the commencement address at his alma mater, Columbia University Law School, Holder made no mention of the Justice Department's investigation of the alleged terrorist plot to bomb Times Square, just a few miles away from the Columbia campus.

Nor did he mention his controversial proposal to try Khalid Sheikh Mohammed, the alleged mastermind of the Sept. 11, 2001, terrorist attacks, and four accomplices in civilian court in Manhattan — a plan that has drawn scorn from law enforcement authorities and city and state elected officials, as well as the families of many of those killed in the attacks.

Holder is now exploring possible other venues for the trial but has said New York is still under consideration.

In his address, Holder made only the barest mention of the world's dangers.

"You are taking leave of this campus in an age of unprecedented challenge, an era of new threats, and a time of war. Yet, you must resist the temptation to feel as though you have been dealt a bad hand," Holder said.

He also made a wry reference to his often controversial tenure at the Justice Department.

"I'm not here to deliver a lecture on the law. I'd say you've had your fair share of those. Trust me, over the past year, I have, too," Holder said to laughs.

Holder graduated Columbia's law school in 1976 after receiving his bachelor's degree there in 1973. He noted how the law had changed in many important ways since he was a student, such as developing a greater recognition of the rights of gays and lesbians.

He said young people had been instrumental in many key changes to the Constitution, including the eradication of slavery, women's voting rights, and the 26th amendment that dropped the voting age from 21 to 18.

That change, Holder said, "ultimately enabled young people to participate in record numbers" in the election of President Barack Obama in 2008.