Primetime is difficult. It can be incredibly unforgiving — especially in this season of high-def politics. The exposure associated with 300 plus million viewers watching every presidential miscue has never been greater. Yet, primetime is the venue that the venerable Obama chose when he turned hope and change into a 24/7 infomercial. That his ratings are slipping is beyond debate. How and when he reached his tipping point is the real cliffhanger. No, his fade is not about policy, and it’s not about politics. It’s not about economics and it’s not about healthcare. It’s about style. It’s about how President Barack Obama jumped the shark in démodé denim.

Shark jumping has its origin in an instant that happened 32 years ago this month. It was on an inauspicious autumn night when most of America had just finished dinner. Unsuspecting and innocent, families of all stripes were winding their day down, yearning for a little respite. They were looking for a break in the bluster of Cold War contentions and deleterious disco. They were hoping to get lost in primetime, in a better time — in Happy Days. What they got instead was anything but happy. For, on the evening of September 20, of 1977, Arthur Fonzarelli (“the Fonz”) traded his patented blue jeans for powder-blue swim trunks and water-skied an entire sitcom into television infamy. On that fateful day, the king of cool donned a crown of kitsch; Fonzie jumped over a shark, and Happy Days became sad.

Before his fall, Fonzie was the incarnation of cool. Conformity, college, convention — none of that mattered. He was an island of grit in a Great Lake of Wisconsin suburbia. His motorcycle, greasy hair, and leather jacket asserted his style. Fonzie didn’t have to prove anything to anyone — especially the American television audience. But, trading a Triumph for a gratuitous grasp at sitcom survival, the brain trust behind the creative curtain took leave of its senses and made a mockery of the Fonz.

That was the beginning of the end for Richie, Potsie, and the entire cast.

Since that unspeakable autumn evening, many seemingly immortal impresarios have followed the Fonz on his allegorical odyssey — pushing their political prestige into obscurity. From the terror of a tank-touting Michael Dukakis, to the primal punch and scream of Howard Dean — those who jump their proverbial shark forever place their best days behind them. They unwittingly outwit themselves and forget who and where they are — more importantly, they forget who put them there.

Obama’s unspeakable act of shark-jumpery, was not actually spoken. It would be somewhat expected to point to his quip about the Cambridge police department; but that actually occurred months after his initial descent. The fact that much ado was made of his comment confirms that he had already fallen from grace — otherwise, no one would have bothered to care about his Cambridge calamity. Neither was it his flat attempt at “Brewski diplomacy” on the South Lawn. Ridiculous as that was, it would have been cheered and lauded by fans of the erstwhile Obama. Nor was it a matter of any other sage or seditious significance. President Obama was not selected for his substance; he was elected for his style.

Until recently, Obama spoke, taught, and presumed with impunity. He was nearly unassailable, so long as he acted and reacted within the parameters of his celebrity — the patented Obama style. His palavering proclivity betokened his commitment to the Obama image. But on July 14, 2009, Obama left style on a hanger and tossed out the first pitch at Major League Baseball’s All-Star Game, dressed in an unfortunate pair of “frumpy” jeans. “For those of you who want your president to look great in his tight jeans,” he explained, “I’m sorry, I’m not the guy.”

Not the guy is right.

The tragic truth of those trousers is that they confirmed the critique of the Obama election. The marginal shift to Obama from the previous Republican administration occurred not because of Obama’s substance or the intricacy of his ideas; people voted for Obama’s persona.

They hoped and changed for a different style. The Nation — 53 percent of them — wanted some slick repackaging.

Obama had it; McCain did not. The Obama mystique convinced just enough voters that Obama’s style would clothe his rhetoric with materiality. As long as his style was impeccable, his message — whatever it purported to be — would resonate. But when style fades, persona follows.

Michael Dukakis jumped his shark in the 1988 presidential election. He staged a perfectly painful photo-op, replete with tank, helmet, and flak jacket.

This ill-conceived venture turned out to be the final maneuver of his campaign, as Dukakis plunged into electoral lethargy and an eventual landslide — for George H.W. Bush. Dukakis: socially minded, executively experienced, compassionately calibrated? — check. Tank-driving tough-guy? — checkmate.

For Howard Dean, style was equally important. Governor Dean had experience and a reasonable record but that wasn’t what excited his sophomoric supporters, it was his status as an irreverent party crasher. A straight-talking spoiler — he was the doctor who made unwelcome house calls to the mainstream of the Democrat party. But on January 22, 2004, Dean’s fist-pumping shriek of honest exuberance was demonstrably uncool and unacceptably unhinged.

Suddenly, the dean of dissent had a fondness for the very same mainstream that he was sent to unsettle. Suddenly, Dean was generically goofy. Suddenly, Howard Dean had jumped the shark.

For President Obama, style is everything — was everything. And spurning style has proven an irreversible pas of the tres faux variety. If only there had been something material to those loose-fitting jeans. If there had been more, his self-deprecating admission would have been endearing. If he had ridden in on something other than a wave of words and artful execution, he might have had something to fall back on. But Obama has nothing to fall back on; his persona won’t allow it. His coronation was a celebration of savoir-faire. He was the advocate of articulation, the sultan of suave, the patrician of parlance. He was supposed to usher in the era of the erudite. He was supposed to show the red-state rubes how consensus is crafted. He was supposed to embody the end of rancor. He was supposed to be the guy who looked great in his stylish jeans.

Turns out he’s just “not the guy.”