Last year’s financial meltdown rightfully destroyed former Federal Reserve Board Chairman Alan Greenspan’s reputation as an infallible “wise man,” but he said something wise in his 2007 memoirs, describing a constitutional amendment he’d been “pushing for years.”

Wrote Greenspan: “Anyone willing to do what is required to become president of the United States is thereby barred from taking that office. I’m only half joking.”

It’s no laughing matter. After all, what sort of person wants the job badly enough to spend years living out of a suitcase, begging for cash, glad-handing through primary states, and saying things that no intelligent person could possibly believe?

Greenspan’s point was that people who seek the presidency today display a pathological power lust that ought to make us uncomfortable, given the powers the modern president enjoys.

George Washington was called “the American Cincinnatus,” after the Roman hero who took power reluctantly and returned humbly to his plow when crisis passed. That’s the model Americans once expected presidents to follow. Things have changed, and not for the better.

The last candidate to pay tribute to the Cincinnatus model was 1996 GOP contender Bob Dole, who praised the virtues of his birthplace, Russell, Kan., insisting it was either the White House or “home.” It turned out that Dole left “home” deliberately vague. After losing, he returned to his condo at the Watergate, making bucks as a lobbyist and Viagra pitchman.

As for the current POTUS, “he’s always wanted to be president,” according to Obama’s longtime friend and advisor Valerie Jarrett. No surprise, then, that, as Newsweek editor Jon Meacham put it in a profile of Obama earlier this year, he “likes and enjoys power,” even “revels” in it.

In a fascinating article, presidential scholar Richard Ellis writes that “in the beginning, the presidency was envisioned not as an office to be enjoyed but as a place of stern duty.” “Powerful cultural norms” told 19th-century presidents to approach the role humbly, with a keen awareness that power corrupts.

In public and in private, early presidents often acknowledged their deficiencies. “No event could have filled me with greater anxieties,” Washington said of his election. Likewise, in his first inaugural, Jefferson worried that the task he’d undertaken was “above my talents.”

Today, Ellis explains, the public demands greater confidence from presidential aspirants. Senate Majority Leader Harry Reid tells us that when he congratulated Barack Obama for a “particularly fine” speech Obama made as a freshman senator, Obama “said quietly, ‘I have a gift, Harry.’ ”

Reid reports that Obama said that with “deep humility.” We’ll have to take his word for it.

Calvin Coolidge, a genuinely humble man and a fine president, wrote in his autobiography that it was “a major source of safety to the country” for the president “to know that he is not a great man.” Few of our recent presidents display Coolidge’s self-awareness.

Newsweek’s Meacham reports that Barack Obama relishes “the capacity to shape reality in his image and by his lights.” An interesting phrase, that — reminiscent of the Bush aide who bragged to reporter Ron Suskind that “we’re an empire now, and when we act, we create our own reality.”

And yet, as we learned during the Bush years, reality has a way of fighting back.

Obama’s supporters have embraced the epithet Suskind’s source coined. They fancy themselves members of the “reality-based community.” Yet they doggedly defend a president for whom the word “hubris” might have been invented — one who thinks that the government, under his direction, can rationally reshape the one-sixth of the U.S. economy devoted to health care.

Our president describes his budget as a “blueprint” for America’s future, and believes that, with the proper mix of social workers and soldiers, we can bring orderly governance to Afghanistan, which has never enjoyed it.

We’d do far better if our presidents had Coolidge’s sense of his own limitations and of government’s as well.

It’s easy enough to blame the overconfident, self-aggrandizing characters who seek the office. But at the end of the day, we’re the ones who reward them. Unless and until we seek out candidates who share Coolidge’s modesty, we’ll have no one to blame but ourselves.