Anthony, Carter is hated by neolibertarians, neoconservatives, and paleoconservatives, so you know there must be much good about him. And indeed, in addition to being the best ex-president of my lifetime--a man dedicated to peace rather than receiving delayed bribes--he was the best president since Eisenhower.
As the head of the American state, he did much wrong. But he also abolished two federal agencies, deregulated trucking and airlines, and held down federal spending. He was less belligerent than other presidents, and he toned down the Cold War. I could go on, but let me mention just this for now: One of his first acts as president was to pardon all the draft resisters who had fled to Canada and other freer lands. That alone makes him a hero.
Now how was he defeated? First, there was a nasty primary campaign against him in 1980 by Teddy Kennedy, on the grounds that he was a conservative; then there were the Iranian hostages. The Reagan-Bush campaign, in secret Paris negotiations with the Iranians, arranged for the hostages to be held until Reagan was being inagurated. The fixer was the evil William J. Casey, ex-OSS spook, ex-ExIm Bank head, Wall Street lawyer, incorporator of National Review, and later Reagan's CIA director. So the Iran-Contra scandals had their genesis in campaign crimes.
You're right: too bad the Dems aren't running Carter, a Southern gentleman in addition, who still teaches Sunday school every week in his little town of Plains, and does a huge amount of personal volunteer work for charity. And he has prevented at least two wars. Compare that to Bush I and his million-dollar speeches and bloody Carlyle Group.