Former presidents aren’t immune from criticism, even when they’re struggling against what might be a terminal illness.

Just ask Jimmy Carter.

Setting that aside, it’s been said many times — usually by Republican politicians — that President Carter’s four years in the White House constituted a “failed presidency.”

Interesting. Let’s look briefly at the record.

Yes, the economy tanked badly during Carter’s term. Why? One reason was the huge spike in oil prices. Lending institutions panicked. They jacked up interest rates way beyond what was normal or acceptable. Inflation took hold. Was all of that the president’s fault? Hardly. But it happened on his watch, so I guess he deserves some of the blame.

The president did a poor job of assuring Americans that they would be all right. He spoke glumly to us, although he never used the word “malaise.”

Foreign policy? Let’s see.

He negotiated a peace treaty in 1979 between ancient enemies Israel and Egypt. He turned them into allies. He took Israeli Prime Minister Menachem Begin and Egyptian President Anwar Sadat to Camp David, clunked their heads together and got them to sign the most important Middle East peace accord in, well, the history of the region. It has held firm to this day.

He helped negotiate a treaty that handed over the Panama Canal to the Panamanians. Imagine that: giving to a nation cut in half by a U.S.-built canal territory that belonged rightfully to its people.

The president signed a treaty with the Soviet Union that helped reduce the number of nuclear weapons in both nations’ arsenals.

Were there missteps? Sure. He didn’t handle the Mariel boatlift of Cuban refugees well. He acknowledged just recently that is one of the regrets of his presidency.

Now, the big one: the Iranian hostage crisis. Fifty-two Americans were taken captive in Tehran in November 1979. The Islamic revolution had overthrown the shah and those “students” were angry because the shah had gotten medical attention in the United States. Was that the president’s fault?

Was it his fault that the mission to rescue the hostages in April 1980 ended tragically in the desert? Just as Barack Obama’s critics have said he took too much credit for the successful mission in May 2011 to kill Osama bin Laden, Jimmy Carter took too much blame for the failure of the Desert One mission to bring our hostages home.

Let us remember, too, that they came home safely on Ronald Reagan’s first day in office. The Iranians clearly wanted to stick it to President Carter by waiting until he no longer was president to end the crisis.

Was it a troubled presidency? Certainly. A failed one? In my view, no.