Former President Jimmy Carter has entered his final days. He has checked in to a hospice to live out his remaining time and, according to an official statement, has refused "additional medical care." So it seemed entirely appropriate to use this year's Presidents' Day to honor him. Carter was an extraordinary man and no matter what opinion you have about his presidency, he has set the absolute gold standard for doing good works as an ex-president -- that much is beyond dispute.

Carter began his career in the military, and while few remember it now he was not just a submarine officer (which is impressive enough) but a nuclear engineer to boot. He was heavily involved in the program which created nuclear-powered submarines and might have been given the command of one of the first of these to be commissioned, but outside events intervened.

I learned about the first of these in a Washington Post article today. The article begins:

The world was in the grip of the Cold War in 1952 when a nuclear reactor began melting down.

That reactor, located at Chalk River Laboratories in Ontario, had suffered an explosion on Dec. 12. Radioactive material had escaped into the atmosphere, and millions of gallons of radioactive water flooded into the reactor's basement. Thankfully, no one was injured, but the Canadians needed help to disassemble the reactor's damaged core.

The United States sent 28-year-old Jimmy Carter.

This wasn't a random choice. Carter had been trained in atomic energy and was an expert on nuclear engineering. What other president can claim such lofty educational credentials? Certainly none that have held the office since Carter's time. The article goes into detail about what Carter had to do to repair the reactor:

In 1952, Carter was selected to join an elite team to help develop the Navy's first nuclear submarines. Once he had trained his crew and the submarine was constructed, Carter was to be the commanding officer of the USS Seawolf, according to Carter in his 1976 book Why Not the Best?: The First 50 Years.

Then the partial meltdown happened, and Lt. Carter was one of the few people on the planet authorized to go inside a nuclear reactor.

Carter and his two dozen men were sent to Canada to help, along with other Canadian and American service members. Because of the intensity of radiation, a human could spend only 90 seconds in the damaged core, even while wearing protective gear.

. . .

"Outfitted with white protective clothes, we descended into the reactor and worked frantically for our allotted time," he wrote.

In one minute and 29 seconds, Carter had absorbed the maximum amount of radiation a human can withstand in a year.

The mission was successful. The damaged core was removed. Within two years, it had been rebuilt and was back up and running.

Carter then missed his chance to command a nuclear submarine because his father died. Carter left active duty in the Navy to go back home and run the family farm instead. Which is how most people remember him before he became president -- as a peanut farmer.

Ironically perhaps, the nation's worst nuclear accident (at Three Mile Island near Harrisburg, Pennsylvania) happened on Carter's watch. He formed a presidential commission to investigate the accident, but if Carter hadn't been president he probably could have served on such a commission himself. He had to walk a tightrope politically on the issue, since the "No Nukes" movement was a growing force in Democratic politics at the time (the anti-nuclear movement was against nuclear weapons and nuclear energy, for those who didn't live through the period). Even though the media made a fuss about it at the time, Carter visited T.M.I. right after the accident and stood 1,000 feet away from the partially-melted core, where he got (as a contemporary newspaper article put it) "less than one-third the radiation of a passenger on a commercial jetliner flying through the stratosphere."

Carter's presidency was a rocky one and he only served one term, getting defeated by Ronald Reagan in an electoral landslide in 1980. But Carter truly began to shine as a humanitarian in his post-presidency. He established the Carter Center to promote human rights around the world -- work which earned him the Nobel Peace Prize in 2002. He worked on peace, monitoring elections, and eradicating disease worldwide. But his most visible presence was his support for Habitat For Humanity, a Christian organization devoted to building homes for poor people both here and in dozens of other countries as well. Carter even taught Sunday school in his local church. Jimmy Carter didn't completely fade from the political scene after leaving office, the way that some ex-presidents do, but he did limit himself to mostly commenting from the sidelines.

All in all, Carter showed compassion and a basic respect for humanity in a way that no other occupant of the Oval Office ever has during their post-presidency. Most either play a lot of golf (and to be clear, that's not a slam on Donald Trump -- in fact, I am thinking of a whole bunch of presidents from Dwight D. Eisenhower forward), or develop a hobby, or just relax and enjoy life. To be fair, for most there is a certain amount of charity and doing good works, but nothing on the scale that Carter managed.

At 98 years old, James Earl Carter Junior will go down in the history books for setting several longevity records: longest-lived president in American history, longest-married president, and the longest post-presidency period. Some of those records may never be broken. But it is my humble guess that Carter will be remembered above all else for just being a decent human being. And that's a pretty good legacy for any politician to end up with, you've got to admit.

-- Chris Weigant

Follow Chris on Twitter: @ChrisWeigant