Hillary better watch it.

The old George Burns adage about sincerity — if you can fake that, you've got it made — remains as true as ever, especially in politics. But in the age of the 24-hour news cycle and total social-media saturation, it's become harder than ever to pull off. All it takes for merciless mockery to go viral is one person on Twitter to pierce the veneer of faux-authenticity with a witty one-liner.

Even Bill Clinton, one of our greatest masters of peddling fake sincerity, might find it difficult to pull off today, two decades after he turned it into an art form on the national stage.

Despite sharing her husband's poll-driven risk aversion, Hillary Clinton has never played the game on his level, and her vulnerability to backlash against gratuitous displays of patent insincerity is already becoming glaringly apparent. Twice within the last week, she's made a fool of herself by presenting a carefully crafted, overly fastidious, and utterly unconvincing version of her opinions. This kind of thing is going to get old very fast if it continues over the (God help us) nearly 29 months between now and November 2016.

And that worries me. I might not be a devoted Democrat, but I am a passionate anti-Republican. Until the GOP's furiously (albeit selectively) anti-government base comes to its collective senses, the party needs to be kept away from the White House. And given the astonishingly lopsided support Hillary has enjoyed so far in the 2016 race, she may be not just the best hope of ensuring that the Republicans remain exiled from the presidency, but the only one.

If she doesn't get her act together, this is less likely to happen.

The first of her two recent blunders was her cringe-inducing exchange about gay marriage with Terry Gross on NPR. Despite what Hillary seems to imply with her increasingly defensive remarks and tone, Gross was not playing a game of gotcha journalism. She was asking a perfectly predictable and legitimate question. Between signing the Defense of Marriage Act and the HIV travel ban, and capitulating on allowing gays to serve openly in the military, Bill Clinton was arguably among the most anti-gay presidents in American history, and certainly no one's idea of a gay rights champion.

Gross was merely asking Hillary, who now supports gay marriage, when and why she changed her views on the subject. Her answer — after Gross asks the question several times in several different ways, and Hillary becomes increasingly agitated — is to say that she simply changed her mind over time, just like everybody else. No political calculation involved at all.

My guess as to the number of informed listeners who found that answer persuasive? Zero.

In fairness, this would be a tough question for any Democrat to answer. Many liberals probably favored gay marriage privately before support began to approach a majority position in polls, which is when the flood of public flip-flops began. And given her husband's record, and her understandable fear of appearing disloyal to him for political purposes, Hillary has a particularly challenging needle to thread on the issue.

Still, the question isn't going to go away. And Hillary's first stab at an answer — making it seem as if politics had nothing whatsoever to do with the evolution of her views — would be unconvincing for any public figure. For a Clinton, it's inconceivable.

And that means that her irritated denial of what we all know to be true makes her sound, even more than your average politician, like someone who could have served as a case study for Harry Frankfurt's vulgarly titled philosophical study of calculated insincerity.

Which brings us to Hillary's second flub of the week.

As part of the promotional juggernaut surrounding the publication of her new memoir Hard Choices, Clinton took part in a "By the Book" interview in The New York Times Book Review. The feature is always a bit of light fun, with an author answering a largely standardized set of questions about favorite novels and authors, influential books, and so forth.

Some of Clinton's answers were predictable campaign fodder meant to make her sound as unassuming and unpretentious as possible. The one book that most made her who she is today? The Bible. (Of course.) When hosting a literary dinner party, what writers (living or dead) would she invite? Shakespeare. (Naturally.)

But what struck me as far more problematic were her long (and longer) lists of favorite books and writers. This is a woman, after all, who since stepping down as first lady in 2000 has served as a senator, run for president, served as secretary of State, and "barnstormed" the country giving $200,000-a-pop speeches, all the while "writing" and now promoting a 600-page book — and, of course, preparing to run again for president.

And yet, remarkably, she also finds time to read. A lot.

Asked for the name of the last truly great book she read, Clinton names four — at least two of which (The Hare with Amber Eyes by Edmund de Waal and The Signature of All Things by Elizabeth Gilbert) just happen to be suburban book-club favorites.

Asked about the "one book" she wishes all students would read, she names three.

Asked about her favorite contemporary writers, she lists nine — and then adds tens more whose "latest installments" she "automatically" reads.

And then there's my personal favorite — the one that inspired me to exclaim "yeah right!" over coffee at the breakfast table on Sunday morning. Asked about her favorite novel of all time, she chooses Fyodor Dostoevsky's The Brothers Karamazov, which she says "made a lasting impression on me when I read it as a young woman."

That's perfectly plausible.

But this is not: "I intend to reread it this summer to see what I now think about it."

Call me a cynic, but I would be willing to bet a significant amount of money that Hillary Clinton will not be curling up on a couch in the sunroom of her home in Chappaqua, New York, this summer with an 800-page theologically infused classic of Russian literature.

Is the BS a big deal? Not really.

As long as the amateurish level of image-tending doesn't continue when it comes to more important topics.

Because there's only so much of this transparent nonsense that sophisticated American voters will accept. Or forgive.