Former president Jimmy Carter talks about his cancer diagnosis and treatment plans. (John Amis/Reuters)

COOL, COMPOSED and as forthright as ever, former president Jimmy Carter said in a news conference Thursday that, in the wake of a cancer diagnosis, he is “perfectly at ease with whatever comes.” The way Mr. Carter handled the conference underscores the grace with which he has conducted his entire post-presidency, and only makes it harder for the rest of us to be perfectly at ease with the possibility of his passing.

Mr. Carter at times has stirred controversy with his deeply held views on the Middle East and other global challenges. Yet even those who have found themselves disagreeing with him, as we have from time to time, have stood in admiration of the honorable life he has lived and the model post-presidency he has shaped. Mr. Carter has spent the years after his single term as president focusing not on constructing a lavish library-memorial, nor on earning millions through speechmaking, but on substantive, civic-spirited initiatives intended to improve the world in ways both big and small.

With the Carter Center, Mr. Carter has advocated for democracy abroad and helped stamp out preventable diseases in underdeveloped countries. His work in both spheres has helped save lives, whether by countering dictatorships or Guinea worms. In and near Plains, Ga., where he grew up and worked as a peanut farmer, Mr. Carter lectures at Emory University, preaches at his local church and teaches Sunday school classes. He even continues to farm peanuts.

Now, as he begins treatment for a cancer that has spread to his brain, Mr. Carter again offers a model of quiet courage, neither fatalistic nor unrealistic, expressing more concern for his loved ones than for himself. We have no doubt that others facing illness will find inspiration in his example.

Despite his diagnosis, Mr. Carter said he still wants to travel to Nepal in November for his 32nd home-building mission with Habitat for Humanity. He also wants to spend more time fishing and with his wife, Rosalynn. Like all Americans, we wish Mr. Carter the best with his ongoing treatment. Any ex-president could do a lot worse than have it said that, after years at the helm, he just wanted to farm some peanuts, save some lives and then go fishing.