Photos: David Handschuh/NYLJ.

Jeh Johnson and Dean Gillian Lester lead faculty to the commencement stage.

Graduate Enrique Colon Baco carries his two-month-old son Nicolas as he shook hands with Dean Gillian Lester.

Members of the class of 1968 lead the procession as one reunion member flashes a peace sign. Protests against the war in Vietnam shut down Columbia's campus 50 years ago as this group attended the school.

Jeh Johnson, former U.S. Secretary of Homeland Security and former general counsel of the U.S. Department of Defense, addressed the Columbia Law School Class of 2018 at a ceremony on Monday held on the South Lawn of Columbia University’s Morningside Campus.

Johnson, who graduated from Columbia Law School in 1982 and is currently a partner at Paul Weiss, told the graduates, “Tolerate and celebrate the diversity of this nation. Respect those who are different, and encourage others to do the same. Intolerance of those who are different reflects a narrow mind and a small heart. I congratulate all those in this class headed to Big Law, including the ten of you who are about to become my colleagues at Paul Weiss.”