Even with his cancer and advanced age of 90, Carter has traveled millions of kilometers and raised millions of dollars without looking back. In 1982, he and his wife, Rosalyn, established the Carter Center to advance the twin causes of peace and health. Among their accomplishments are the near elimination of the Guinea worm disease and helping establish a village-based health care delivery system in thousands of African communities.

Two years later, the Carters became associated with Habitat for Humanity, an NGO that uses volunteer labor to build homes that are sold at no profit - 800,000 so far all over the world. Habitat and the Carters have a project in Southeast Asia and China's Yunnan province, whose goal is to build homes for 50,000 families in five years.

Now, given his candor and humanity, I'm sure Carter will help educate people about cancer. In 1971, Nixon declared a "War on Cancer" aimed at eliminating the disease. But billions of dollars and millions of deaths later, scant progress has been made. Again, leading by example, Carter will make a difference in fighting this battle too.

Before, during and after his time in the White House, Carter set a great example as a moral leader. Few people remember that he led Sunday school lessons while in the White House, as he does in Georgia to this very day. President Xi Jinping's difficult fight against corruption has turned him into a moral leader too. Both courageously chose to stake out the moral high ground irrespective of the personal costs.

Let's hope Carter wins his battle against cancer. His situation is grave. But miracles do happen. If a peanut farmer from Plains (population 700-plus) in Georgia could become the 39th president of the United States, anything is possible.

The author is a senior adviser to Tsinghua University and former director and vice-president of ABC Television in New York.