Sarah, we hardly knew ye.

But we knew ye well enough to not want to know ye any better.

Thanks for sparing us.

Thanks also for the diversion you provided three years ago, at a time when the nation needed a laugh. But it’s now time for the grownups to get on with the serious business of the 2012 presidential campaign.

Sarah Palin’s announcement Wednesday that she would not enter the race for the Republican nomination came as no surprise to the political establishment, including almost all Beltway pundits.

Nor did it surprise me. In researching my new book about her, The Rogue: Searching for the Real Sarah Palin, I learned enough about her opportunism, her narcissism, and her essential unseriousness to come away convinced that however much she might yearn for the powers of the presidency, she doesn’t have the heart or the mind needed to wage a sustained campaign for the office.

I actually said as much on my blog on Tuesday, the day before her announcement.

I wrote:

You’ve always said that your God tells you what to do, and opens doors for you.

Sarah, the door will never be open wider, nor the sea more parted, than it is right now.

Will you have the courage to walk through it, and enter the race?

I don’t think so.

And it’s not because The Big Guy in The Sky is telling you not to.

It’s because you can’t face the scrutiny.

As vice presidential nominee, you got a free pass in 2008 from mainstream media.

And MSM has allowed you to become a multi-millionaire celebrity ever since. They are complicit, tacitly agreeing not to show you up as a fraud as long as you give them ratings, web hits, and newspaper circulation.

But too many eyes are now watching, and MSM won’t be able to do it again.

Sarah, the road show is over. I know you’ll quit while you’re ahead.

Alaskans, certainly, are not surprised. After all, Sarah not only quit as their governor when a more lucrative opportunity from Fox News came along, but in 2004 she quit her appointed position on the Alaska Oil and Gas Conservation Commission because her duties bored and confused her, and she didn’t like the hour-long daily commute from her home in Wasilla to her Anchorage office. The only job Sarah ever had that she didn’t quit was being mayor of Wasilla, and she stuck that out for six years because she was able to hire a deputy administrator, John Cramer, a fellow evangelical Christian, to do her work for her. Seven weeks before the end of her second and last term as mayor—because she was by then running (unsuccessfully) for lieutenant governor, and didn’t need him anymore—she fired Cramer.

So whither Sarah now?

Or should I ask: will Sarah wither now?

I think she will, because there never was a there there.

She was a novelty item, presented in gaudy wrapping paper by a desperate John McCain to a jaded mainstream media. And she gave a knockout speech at the Republican convention in Minneapolis in 2008. To that single occasion, she rose, and performed brilliantly. But it’s been steeply downhill ever after.

By opting out of next year’s race, Sarah has betrayed her ever-shrinking base. The Tea Party will never drink a cuppa in her honor again. She cynically manipulated her gullible enthusiasts, knowing all the while that she never intended to run.

She may drift into the Sargasso Sea of daytime television, where she can chat up B-list celebrities. But there’s no reason now even for Roger Ailes to renew her contract at Fox News. Just Tuesday, Ailes said, “I hired Sarah Palin because she was hot.” She’ll soon be as cold as the shrinking Alaska glaciers that are melting from the global warming that Sarah doesn’t believe is caused by man.

The single most important thing I’ve learned about Sarah since I started researching her on election eve, 2008, is that the only person she cares about is herself. She’s not the first politician—make that ex-politician now—to have purveyed a false image. But going back to The Selling of the President, my book about Richard Nixon’s successful campaign for the presidency in 1968, I have never encountered a public figure whose façade was so entirely false.

I write in The Rogue that “Sarah Palin practices politics as lap dance, and we’re the suckers who pay the price.”

We dodged a bullet in 2008. An uninformed, incurious, emotionally unstable religious extremist used dazzle and dash to get within 7 percentage points of being a heartbeat away from the presidency.

In our 235 years as a nation, that might have been—other than the Civil War—the gravest threat our republic has ever faced. Not only was she the most unqualified candidate in our history, she might have been the most mentally fragile, and she was certainly the only one ever who flirted openly with the notion of ending the separation of church and state.

Sarah’s venality and lack of gumption assure that we’ll not have to face the same threat next year. For that, we should give thanks to God.

Arrivederci, Sarah.