(NewsNation) — Jimmy Carter was “the most impactful one-term president” in modern American history, according to his former domestic policy adviser Stuart Eizenstat, who defended the 39th president’s legacy following Carter’s death Sunday at age 100.

Eizenstat, speaking with NewsNation before Carter’s passing, cited the former president’s achievements in energy security and foreign policy, arguing that Carter’s presidency laid crucial groundwork for America’s future despite his 1980 electoral defeat to Ronald Reagan.

“The energy security which we enjoy as a country today, the lack of dependence on OPEC oil… rests on the foundation of three major energy bills that he passed,” Eizenstat said.

He also credited Carter for initiating defense programs that would later be associated with the Reagan administration, including the cruise missile and stealth bomber.

His post-presidential work through the Carter Center included monitoring over 100 democratic elections and helping combat diseases in Africa.

“This was a life well lived,” Eizenstat said, “not just in longevity, but in its impact from the time he got into public life and served as a submariner to the time he passed away.”