Most everyone seems to agree that what many Americans have been looking for from presidential candidates lately is "authenticity."

If so, they likely are headed for eventual disappointment; it may already have begun to set in — much as they would be out of luck seeking flamboyance from their accountants, or caution from their daredevils.

Authenticity doesn't come naturally to politicians, if it means saying exactly what one really thinks and agreeing only to what conforms to one's purest principles. And the truth is, we shouldn't want it to.

In the end, the whole point of representative democracy is that we elect individuals to govern but not to rule — to lead, yes, but also to heed, at least at times, the will of the people.

And America's constitutional system, by dividing governing powers, makes tact, salesmanship and flexibility the true coin of the realm, at least in the absence of elections producing sweeping, one-party mandate victories of a kind not seen in half a century.

But so far in this campaign, the most motivated constituencies have seemed to hunger for a political style that is at once more snarling and less serious. Wisconsin Gov. Scott Walker, struggling to catch a breeze, tried to name and claim the coveted quality last week. Promising to carry his anti-union crusade to Washington, Walker declared: "I think if people are looking for someone who is truly going to … wreak havoc on Washington … I'm the only one."

The only one? The GOP demolition derby includes more would-be havoc-wreakers than problem-solvers, and last week's debate showed once again that, try as he might, Walker is simply not the most authentic emblem of the essentially puerile vandal spirit that has often possessed this campaign so far.

Until last week, no rival in the Republican race had found a way even to compete with the fake authenticity of Donald Trump, who, in his curiously capitvating, malaprop-laden repetitive verse, rubs raw the class and race resentments of white, working­-class Americans — against foreigners who are stealing our country (they've stolen it; it's gone) and the very, very stupid and incompetent people in Washington who are letting that happen (I'll make great deals, terrific deals, unbelievable deals).

But last week a moment of actual authenticity befell this never "bragadocious" but proudly "militaristic" gasbag, when Carly Fiorina staggered the Donald with her cooly cutting "women-know-what-he-said" comeback to his suggestion that Fiorina's "face" undermines her electability. Perceptive enough to realize retreat was his only option, Trump could only ooze with the childishly fulsome flattery that he suddenly thinks Fiorina has "a beautiful face."

Trump fared only a little better toe-to-toe with Jeb Bush, from whom Trump's provocations inspired flashes of not so much "energy" as of something resembling authentic grit in defending his wife and even his brother. Meanwhile, Trump, beating another disorderly retreat, explained of his earlier complaints about Bush's sometime speaking Spanish on the campaign trail that "I did it a little bit half-heartedly, but I do mean it to a large extent."

Everything clear now? (One supposes, by the way, that he meant he did it "half in jest" — but, hey, English can be a tough language to master.)

Whether or not any of this humbug can dent Trump's "authenticity" armor and permit the GOP race to grow up, the authenticity mirage is shimmering for Democrats in their nomination journeys, too.

Strangely, Hillary Clinton may be the most demonstrably genuine candidate in either party, but it doesn't do her a bit of good. Clinton has been prominent in public life now for a quarter-century-plus, and all that time she has displayed exactly the same emphatic character and personality — smart, competent and tough, on the one hand; cold, calculating, secretive and brittle, on the other. Say what you will, this is who she is — living proof that real authenticity doesn't always sell (while her husband remains evidence for the allure of the manufactured kind).

Clinton's trouble is that her competition has authenticity, too, maybe of a more appealing flavor. Vermont Sen. Bernie Sanders is an authentically zealous leftist, self-proclaimed socialist, and moralist scourge of the wealthy. A Sanders presidency might bring even more chaos and paralysis than we've become accustomed to in recent years — but he is the real thing for Americans on the left who are "looking for someone to wreak havoc."

And of course Vice President Joe Biden, if he ultimately runs, will almost have set a new standard for wrapping the aura of authenticity around a candidacy. Biden's much discussed grief for his recently deceased son, Beau, is unassailable; his uncertainty about whether, in its wake, he can summon the passion and conviction to seek the presidency is touching and impossible not to understand. Biden displayed both with dignity and humor in a memorable appearance on the "Late Show with Stephen Colbert."

And yet, at the same time, what a story line — what a poignant narrative with which to hold the country in suspense about a decision whether to launch a campaign. Introducing Biden, Colbert gushed that what America likes so much about the vice president is that he's not the sort who would ever "triangulate your … emotional state to make us feel a certain way." Of course not. Yet voters always need to be careful. Gut feelings matter about whether candidates' judgment and character can be trusted, because we can't know what issues a future president may face. But the appearance of "authenticity" may simply not be the most authentic qualification for this particular job.

D.J. Tice is at Doug.Tice@startribune.com.