Thinking of Walter Mondale near his 90th birthday: A great leader. A great teacher.

As Walter Mondale turns 90 this month, I find myself reflecting on the improbable relationship he and I have come to enjoy. My ties to Vice President Mondale didn't come through party loyalty but through teaching a course with him at the University of Minnesota on the U.S. Constitution and national security — for nearly 15 years.

I was filled with curiosity and trepidation when I approached our first meeting all those years ago. I'd never taught with a former vice president, or for that matter with a former Minnesota attorney general, former U.S. senator or former ambassador to Japan. But we quickly formed a team to introduce students to debates since the late 18th century over whether presidents can act alone to take America to war, to reach diplomatic agreements, and to spy on and raid private property.

But Mondale has taught our students — and me — more than just history. Here are some of the lessons he offered:

One of Mondale's cardinal rules is to never assume, or act as if, your ideas are better than anyone else's. He often quotes the great Judge Learned Hand, who observed that "the spirit of liberty is the spirit which is not too sure that it is right."

About 15 years ago, the vice president and I traveled to the Carter Library to bring back documents relating to Mondale's work in the Carter administration. The documents would become part of a collection at the Minnesota Historical Society, enabling our students to study the inside story of the Iran hostage episode; Mondale's diplomatic steps that started to undermine the vicious racial system of apartheid in South Africa; his historic trip to China that began to normalize trade relations and initiate — until recently top-secret — national security cooperation; the transformation of the U.S. weapons systems from mechanical to digital systems; and much more.

At the Atlanta airport on our way back to Minnesota, I secured dinner for us in two paper bags. But I was stopped outside the frequent-flier lounge, which prohibited food. I began to say, "I am here with the vice president," but Mondale waved me off. "We're no different," he said.

We proceeded outside, and soon Mondale was surrounded — as he must have anticipated, given his famed connection to Atlanta's favorite son, former President Jimmy Carter. He greeted everyone with an easy laugh and genuine interest — including some Republicans with long-standing bones to pick. Of course, his food got cold.

A few years later, after a public program with Mondale, a woman congratulated me on my good fortune to teach with the vice president, and I gushed, "I can't believe I get paid to do what I do!"

Later, as I drove Mondale home, he said, kindly but firmly: "I don't want to ever hear you say that again. How do you think you made that woman feel?"

I was born in Brooklyn and raised near New York City, where humility isn't prevalent, but I've thought about pridefulness ever since.

Professors are comfortable in the world of abstraction. Not Mondale, who reoriented my approach to teaching by insisting that we put our students in the real world where presidents face difficult situations.

Take Democratic President Harry Truman during the Korean War. Urgently needing steel to equip troops engaged in ferocious battle, he faced an indispensable political ally (unions) demanding salary increases after little improvement for years, and steel plant managers refusing to accept arbitration. Truman's response: seize privately owned steel mills, setting off a fiery debate that produced a landmark (unanimous) Supreme Court decision reversing his action. (Historical footnote: All of the justices voting against Truman had been appointed by Democratic presidents.)

What would you have done in Truman's place? Here are a stack of historical and constitutional materials to read carefully. Now, make the argument for the position you initially opposed.

That's Prof. Mondale's approach.

Favoring the practical over soaring rhetoric was a theme during Mondale's government service — a pattern I became quite familiar with when I facilitated work on his memoir, "The Good Fight." When he served in the U.S. Senate from 1964 to 1976, Mondale worked with conservative icon Barry Goldwater and other Republicans to expose abuses of power by the FBI and CIA, focusing on the tangible impacts on everyday Americans.

When Sen. Mondale pressed the director of the FBI about the illegality of bugging and harassing the Rev. Martin Luther King Jr. and other Americans for exercising their rights to speak their minds and protest, the head of the country's law enforcement lamely tried to defend himself: "Sometimes you have to give up some rights to protect others." Mondale swooped in with a simple, devastating question: "Would you tell me which rights you'd give up?"

Years later, the conservative Republican U.S. Rep. Jim Sensenbrenner visited our class. He nodded to his political differences with the vice president but fervently embraced their shared commitment to fending off government abuse of our constitutional rights to freely assemble and speak out against our government, to enjoy privacy without government intrusions unless independent courts approve them, and much more.

Over the years, I came to appreciate Mondale's deep religious moorings in the "Golden Rule" — "do unto others as you would have them do unto you." These values, instilled by his devout mother and minister-father, propelled him to become a leading congressional force for civil rights and equal access to education, which opened the doors of opportunity for all Americans, including people of color and women.

Practicing the values of morality and justice led Sen. Mondale not only to vote — with Republicans — for the landmark civil-rights legislation of the 1960s but also to take the lead in enacting the Fair Housing Act that barred discrimination concerning where we live. (His staff greeted the news that he'd volunteered for what many thought was a political suicide mission with a somber, "Thanks, Boss.")

Later, he joined Republicans in extending educational opportunity by playing a leading role in creating Title IX — a step that, among other things, brought girls out of the grandstands at sporting events and onto the field of play, spreading the thrill of their accomplishments to every community in America.

He broke another barrier by choosing U.S. Rep. Geraldine Ferraro as his running mate when he ran for president in 1984. Shattering that glass ceiling cleared the way for Hillary Clinton to seek the presidency in 2016 (and perhaps for Condoleezza Rice in the future).

Here is the teachable moment: Aligning policies with core American values weaves even contentious new ideas into the fabric of everyday life. Do you consider our overflowing programs for girls' volleyball to be political? Of course not, but that's the point — it took some determined souls in Congress to insist on fairness in distributing funding for boys' and girls' sports.

On election night 1984, after it was clear Ronald Reagan had won, candidate Mondale appeared in front of his downcast supporters to thank them and report that he had congratulated President Reagan on his re-election. Speaking firmly and insistently over murmurs of discontent from his supporters, he spoke to a higher loyalty:

"We are all Americans," he said. "He is our president, and we honor him tonight."

Mondale is not shy about sharing his reservations regarding our current president, but he is also careful to describe him as "our president."

Not long ago, current Vice President Mike Pence called Mondale, who welcomed the gracious gesture. I have no idea what they discussed; Mondale keeps the content of their conversation to himself.

I sometimes worry that loyalty to our country's enduring values and the search for shared community are giving way to overriding personal ambition and unrestrained displays of ego. That is not our history, as Mondale and leaders from both political parties have demonstrated.

A few years ago, Mondale spoke to Minnesota legislators from both political parties at a retreat at the University of Minnesota's Humphrey School of Public Affairs: "My dad, a small-town farmer-minister from Elmore, always talked to us about doing justice, loving mercy and walking humbly," he said. "These are not partisan goals; these values — and the grace to serve them — are at the center of our lives."

At a time when our politics reeks of hate, legislators from both parties were listening, not as rivals but as Minnesotans with a shared hope.

I thank my lucky stars for the unique opportunity of learning from Walter Mondale. On the grandest of stages, he has won and lost with grace, counseling humility in victory and hope for the future at moments of disappointment. He fittingly ends his memoir quoting the Apostle Paul: "I have fought the good fight, I have finished the race, I kept the faith."

Can I get an amen?

Lawrence R. Jacobs is the Walter F. and Joan Mondale chair for political studies and director of the Center for the Study of Politics and Governance in the Hubert H. Humphrey School at the University of Minnesota.