With President Donald Trump having refused until Monday to permit government officials to cooperate with President-elect Joe Biden's team during this presidential transition, it's worth remembering that cooperation between outgoing and incoming administrations previously has been a proud U.S. tradition.

Sharply differing worldviews have not prevented close coordination between political rivals. We must re-establish this norm as we look to future transitions — and look beyond Trump's current efforts to burn down the proverbial house before he departs.

I have been involved in three presidential transitions, two of which involved outgoing Bush administrations. In 1992-93, I served on Bill Clinton's state department transition team, and in 2008-09, I led the Barack Obama transition team at the U.S. Mission to the United Nations, in support of incoming U.N. Ambassador Susan Rice. In each of those experiences, officials of the outgoing Republican administrations extended every courtesy.

But I may have experienced the most impressive examples of comity and cooperation when I served as a Clinton White House staff member after the 2000 presidential election. On Dec. 12 of that year, the Supreme Court settled a Florida recount dispute and provided George W. Bush the definitive electoral victory. Of course, that meant a decidedly shortened presidential transition, with much less time for President-elect Bush and his team to prepare for the overwhelming responsibilities they were about to assume.

As the end of that year approached, I expected to depart the National Security Council when George W. Bush was inaugurated on Jan. 20, 2001. After all, I was a Clinton presidential appointee and a long-standing member of the Democratic Party's foreign policy community.

What's more, in my White House position at the National Security Council, I had strongly promoted a controversial Clinton administration initiative — U.S. signature on the Rome Statute for an International Criminal Court — which was anathema to the incoming Bush administration.

Thus, it was with some surprise that I learned the incoming Bush administration wanted some of us to remain in our jobs following the inauguration. Quite simply, the truncated transition had given the new administration less time to prepare, and they needed help. Less surprising to me was the position of Clinton's national security adviser, Sandy Berger, who indicated that I should indeed remain during an interim period to help the new administration.

In short, we were to help the new administration, no matter how much we might have abhorred some of its policy perspectives.

And the Bush team reciprocated. Before Jan. 20, I was visited in my office at the National Security Council by the incoming deputy national security adviser, Stephen Hadley, who was gracious in making the request for help and in making it very clear that my contributions and those of my staff would be deeply appreciated and warmly welcomed. We agreed I would serve the new president.

I confess it was a somewhat surreal experience for me to see the likes of Donald Rumsfeld (the newly appointed defense secretary) walk into a White House Situation Room I had long associated with Democratic national security types such as William Perry and Madeleine Albright. But no matter: I was treated with great respect by my new colleagues, and especially by Hadley and his boss, National Security adviser Condoleezza Rice.

More important, they continually sought me out for information and advice on the issues they were confronting. About six days into the new administration, an earthquake struck the Indian state of Gujarat, and both Hadley and Rice were eager to demonstrate to the government of India a strong commitment by the new administration to humanitarian assistance. We worked closely and cooperatively on this important issue.

Throughout my short tenure as a senior NSC staff member in the George W. Bush administration, my presence was welcomed, my perspectives were solicited, and my contributions were valued and respected.

The contentious and inflammatory posture of the Trump administration has made it difficult to imagine the spirit of common purpose that enabled this unusual and valuable arrangement between the Clinton and Bush administrations back in 2001.

While the current strife may be a tragedy for our country, it only underscores the importance of regaining the comity and cooperation that now seems a distant memory.

Eric Schwartz is former dean of the Humphrey School of Public Affairs at the University of Minnesota. He served in senior diplomatic positions in the Clinton and Obama administrations. He is currently president of Refugees International.