During a presidential debate in 1984, Ronald Reagan, who was then 73, famously said of his opponent, Walter Mondale, who was then 56 and trying to make an issue of Reagan’s age: “I am not going to exploit for political purposes my opponent’s youth and inexperience.”

The joke turns, of course, on the reasonable assumption that, as a rule, experience is a good thing and inexperience is a bad thing.

Mitt Romney started this year’s presidential campaign with the same assumption. So did other Republicans. “Inexperienced” was their favorite one-word accusation against President Barack Obama. It is witheringly dismissive without seeming overtly hostile or in any way racist. Come back in a few years, sonny, when you’ve had some experience. Even Mahmoud Ahmadinejad, the president of Iran, called Obama “inexperienced,” though I guess that’s a step up from “the great Satan.”

If politics were a resume contest, Romney’s would be hard to beat. Successful private businessman. Generally successful one-term governor. Saved the Salt Lake City Olympics.

Or so everybody thought, including Romney. Thanks to Newt Gingrich and Rick Santorum, though, the whole successful-businessman theme has turned from a plus to a minus.

And this is in the Republican primaries. Romney has now been repositioned by his opponents as a rich guy who enjoys throwing people out of work. We hear almost nothing from Romney about his accomplishments as governor. He might as well have been out of work (as he foolishly -- and briefly -- claimed) and playing tennis at the country club, for all that anyone would care. In fact, in some ways he would be better off today if that’s what he’d done.

Washington Experience Unwanted

So now Romney emphasizes his own inexperience -- in particular, his inexperience of Washington. It plays a larger role in his campaign than his experience as a governor and businessman. He knows nothing about Washington, he says. Couldn’t tell you which monument is Washington and which is Lincoln. By contrast Gingrich spent 20 years in Congress, rose to the No. 3 position in the government and feels he must be defensive about it. If Santorum hadn’t lost his race for re-election to the Senate by 17 percentage points six years ago, he probably would not be running for president now.

Not only is planning and executing a run for the presidency a more-than-full-time job (and if you miss any Senate votes while doing it, you get tarred as a slacker), but there’s a great rhetorical advantage in being out of office. The experience of being in office just gets you in trouble.

In a debate last fall, Texas Governor Rick Perry pretty much played his assigned role as the heavy except for one moment, when he defended his support for a Texas law allowing the children of illegal immigrants to qualify for in-state tuition at state colleges. If you disagreed with that policy, he said, “I don’t think you have a heart.” As far as I know, it was the first (and last) sign that Perry has one, and -- along with the immortal “oops” a couple of months later -- it took him out of the race.

Then there is the “individual mandate” -- a critical feature of both Romney’s and Obama’s health-care plans, designed by conservatives. How was Romney supposed to know, back when he pushed it through as governor, that it would become a symbol of the (yet to be experienced) excesses of Obamacare? Romney no doubt wishes he had never heard the term “individual mandate,” or attempted to tackle this huge social problem as governor.

It’s preposterous that experience in government should be a disadvantage in running for president. But we’ve reached the point where actual current government service (except for the sitting president) is almost disqualifying, past government service is a disadvantage, and no previous experience is necessary.

Gotcha Politics

Nasty “gotcha” politics are part of the problem. They can’t attack your record if you’ve got no record. That was one of Obama’s big advantages in 2008, when he’d been in the Senate for only three years. You get no points for years of government service, but some long-forgotten vote can come back and haunt you. So the fewer votes, the better. Or now the very fact of long and loyal government service is a weapon to be used against you.

Citizens may be genuinely and rightly angry at the government’s failures. More likely, they are unreasonably disappointed that the government can’t suspend the laws of mathematics and solve our economic problems in a snap. The politicians are at fault for making promises they can’t keep, but the voters are also to blame for believing the promises -- in fact for insisting on them.

We haven’t yet elected one of those know-it-all businessmen with no political experience, like Lee Iacocca or Ross Perot. But Romney is pretending to be that person, and he’s still the second-most-likely person to be president a year from now.

(Michael Kinsley is a Bloomberg View columnist. The opinions expressed are his own.)

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To contact the writer of this article: Michael Kinsley at mkinsley@bloomberg.net.

To contact the editor responsible for this article: Michael Newman at mnewman43@bloomberg.net.