Editor’s Note: Julian Zelizer is a professor of history and public affairs at Princeton University and a New America fellow. He is the author of “Jimmy Carter” and “The Fierce Urgency of Now: Lyndon Johnson, Congress, and the Battle for the Great Society.” The opinions expressed in this commentary are his.

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Julian Zelizer: At courageous press conference, Carter talked openly about his cancer diagnosis and Carter Center's future

Carter's remarkable achievements in past decades have redefined the post-presidency, Zelizer says

CNN  — 

Former President Jimmy Carter’s personality was on full display at his courageous and somber press conference. His commitment to his family and devotion to his work, and his willingness to talk in a direct way about almost anything, including his health, reflects the kind of person he has always been. His optimism and calm in the face of difficult challenges is also classic Carter.

Julian Zelizer

The conference marked the end of an important era in presidential politics. In his remarks to reporters, Carter made it clear that as a result of his battle with cancer he will pull back from many of his involvements at the Carter Center so that he can undergo the necessary treatment. Joking that he and wife Rosalynn have been talking about slowing down his work schedule for many years, now he acknowledged the time had come to begin this process.

Since leaving the White House in 1981, Carter has remade the post-presidency. It will never be the same again. Using the Carter Center in Atlanta as his base of operations, Carter has remained a hugely influential figure in public life. He has acted as a rogue diplomat since the 1980s, working in regions such as Central America to ensure the fairness of democratic elections and advocating policies – often highly controversial ones – about how to obtain peace in regions like the Middle East and North Korea. Throughout, he has continued to fight for his belief in the centrality and effectiveness of diplomacy as an alternative to war.

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Jimmy Carter: I thought I had a few weeks left
00:59 - Source: CNN

Sometimes Carter has proven to be an ally to presidents as they seek to achieve difficult goals overseas. Other times, as was the case when Bill Clinton was president, he has been a thorn in the side of the White House as he took steps that didn’t fit with the president’s agenda. Besides war and peace, he has been very involved in combatting international health problems such as with his Guinea Worm Eradication Program.

Within the United States, he promoted humanitarian volunteerism through Habitat for Humanity. Carter has also promoted his ideas as a best-selling author. Although he ended his time in the White House as an unpopular president, he has ironically proven to be a hugely successful writer whose works have helped shape public debate.

As he explained to the reporters in the room, the presidency was the most important political experience in his life, but his work with the Carter Center has been more “personally gratifying” as he was able to help individuals and families in the most impoverished regions of the world.

Even though he is pulling back, his impact will continue to be felt in American politics. No longer will presidents fade into the background once they leave office. Even though Carter did many things wrong when he was in the White House, he has set a new standard for ex-presidents as to how to use the public capital that comes from holding office to influence public debate and continue to have an effect on public policy.

As President Obama figures out what to do next – he recently announced the creation of “Brother’s Keeper,” a nonprofit to help young African American men – Carter is a healthy reminder that the post-presidency should not just be primarily about fund-raising. Bill Clinton’s activities in that area since his time in office have caused many people, in both parties, to be uncomfortable.

In an ideal world, Carter has offered a model of how to use this role to advocate for certain ideas and to actually be involved in public policymaking outside of the partisan sphere.

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