Here at American Thinker last week, my friend Herb Meyer wrote a piece that's getting a lot of attention. He noted that as the Obama administration erupts into scandal, we look everywhere for a smoking gun leading back to the president. Don't bother, cautions Meyer. If you study history, you'll realize few such documents ever materialize. The example he cited has gotten much attention: "Very few people are aware of this, but there is no document -- not one -- linking Adolf Hitler to the Holocaust. Why not? Because Hitler didn't need to sign a document ordering the slaughter of six million Jews." All that Hitler needed to do, notes Meyer, was demonize his enemies and then hire thugs like Reinhard Heydrich, Heinrich Himmler, Adolf Eichmann, and Josef Goebbels to do the rest. They knew what he wanted, and then they handled the details.

Meyer carefully warned that Obama and his minions are in no way comparable to Hitler and his. "That's absurd," he writes. "I am merely pointing out that President Obama has been going about the business of demonizing his political enemies, and then hiring thugs to destroy them without regard to the law, in precisely the same way that Hitler and his fascists did it in Germany. This isn't an accusation; it's an observation."

I reiterate that caveat here. As Herb Meyer and I both know, it does a disservice to the horrific evil orchestrated by the Nazis when analogies to the Holocaust are misplaced or exaggerated. The analogy here, as Meyer says, is used merely to drive home a point that people will understand.

With that same caveat, I would like to pick up the analogy, because Meyer is indeed on to something that should worry us greatly, especially given the political psychology of American liberals.

A book came out in 1996 called Hitler's Willing Executioners, by Daniel Goldhagen. The book remains controversial with (rightly so) plenty of detractors. But Goldhagen's principal argument has merit -- namely, that Adolf Hitler himself never killed a single Jew; rather, it took countless thousands and millions of ordinary Germans to carry out -- to execute -- Hitler's plan. In this, Goldhagen was exactly right, and his observation ties back to Meyer's thesis and, more so, what I've long feared is happening with the American Left.

What Hitler and his minions did was thoroughly demonize their enemies, convincing the German masses that Jews and other despised groups were subhuman, untermenschen. A major factor in Hitler's political advancement was his amazing ability to fabricate an assortment of handy scapegoats for the nation's ills. He got away with blaming anyone but himself for whatever calamity or misfortune. As he did, his followers assented, nodding their heads and bleating like sheep.

What the American Left has done to its enemies is not entirely dissimilar, even while certainly not approaching the crass, deadly level of the Nazis. But whether it's Obama himself, or his campaign, or Media Matters or MoveOn.org or any number of left-wing groups and websites and publications and media outlets, the American Left has been merciless in thoroughly demonizing opponents. Liberals don't just politely disagree, or agree that people can disagree; no -- too often they caricature those who disagree as vile reprobates with no possible good intentions or reasoning for their positions. It's a very illiberal thing to do.

Take the Tea Party, for starters. Once they saw the Tea Party's effectiveness, especially after the 2010 midterm elections, liberals/"progressives" went on a rampage, smearing the wide swath of Tea Party members (whom they probably never met) as recalcitrant racists. It was a charge totally unfair and ludicrous. I know people in the Tea Party. I watched the group develop. They are absolutely not racists; they were driven completely by the fiscal madness of Obama and the Pelosi Democratic Congress in the first six months of Obama's presidency. But once liberals starting ramping up their crude caricature, with congressmen and NPR executives and respected left-wing journals of opinion like the New York Times leading the way, the liberal mob responded in kind. Tea Party members were labeled as the worst kind of "extremists."

The result was shocking to behold. Like wildfire, liberals/progressives everywhere were swept up, fuming with anger and fanning the flames. They mimicked the party line without any question whatsoever. They whipped themselves into an emotional frenzy, convinced with absolute righteousness that this insidious group of racists was trying to undermine the saintly, kindly Obama for no reason other than the color of his skin.

As conservatives, we saw from the outset that this was pure politics -- actually, pure political demagoguery. Conservative talk-shows played clips from select liberals (such as Chuck Schumer) admitting as much. We saw right through it. But liberals don't think that way. They aren't wired that way. They're incredibly emotional people who can be easily prodded by their party/ideological elite, especially with the spontaneity and instant communication of social media -- the new mother's milk of the liberal mob. They really are prone to fads and fashions and mass behavior in ways that conservatives plainly aren't. I've seen it again and again. Conservatives aren't perfect, and have their own quirks and vices, but they don't tend toward this kind of group thinking and collective action. For conservatives, the ability to think logically and independently, based upon beliefs and values deeper and timeless, and to not be seduced by what Pope Benedict XVI calls the "anonymous power" of the latest fads and fashions, is what makes them conservative to begin with.

And so, when word was out among the Left that the Tea Party was comprised of genuine evildoers, the wider liberal masses, whether at blogs and nonprofits and Facebook or working for the IRS not only responded; they retaliated. They acted naturally. They didn't need Obama to tell them what to do. Exactly as Herb Meyer says, there was never any need for a printed order from Obama.

Tea Party aside, the American Left is also viciously targeting those who dare to oppose gay marriage. Here, too, liberals/progressives refuse to agree to disagree. Those who stand for traditional marriage as people have understood it since the literal dawn of humanity are framed as awful people, as intolerant "haters," almost subhuman in their lack of compassion. They are a form of modern American untermesnchen, utterly despised -- contemptible. 

When an Oregon couple, a baker and his wife, declined to make a wedding cake for two members of the same sex, the apostles of tolerance and diversity went screaming mad, attacking the couple with profanities and threatening lawsuits -- with no respect at all for the couples' freedom. "You stupid bible thumping, hypocritical [expletive]," wrote one loving liberal in an email. "I hope your kids get really, really, sick and you go out of business." Another champion of compassion added: "Here's hoping you go out of business, you bigot. Enjoy hell."

Organizations trying to stop gay marriage -- that is, trying to stop the redefinition of marriage, and believe that children need a mom and a dad -- are being derided as "hate groups."

A near-tragic example happened with the Family Research Council, which was labeled a "hate group." I know people at the Family Research Council. They are good-hearted, classic social conservatives. Their social positions aren't different from where the Democratic Party stood for over a century.

But once an organization of "civil rights" liberals labeled the Family Research Council a "hate group," the charge went viral, and then, one fateful day last August, an enraged homosexual activist headed for the group's offices with an arsenal of bullets and weapons poorly concealed in Chick-fil-A bags. He was stopped only by an alert security guard, who was shot and injured.

This left-wing gay activist, convinced that the Family Research Council was promulgating "hate," was prompted to an act of attempted mass murder.

This example should be widely known. It isn't. Why not? Because the mainstream media hasn't made it a national issue. If this had been a conservative shooter targeting a liberal organization, with a conservative president in the White House, all of conservatism would be held complicit, and the media would demand the president condemn the action. There would be a national media campaign against "conservative extremism."

Speaking of Chick-fil-A, it, too, has been a target of leftist rage: boycotts, protests, pickets, mayors of big cities trying to ban the restaurant and describing its product as "hate chicken." Why? Simply because the CEO is against gay marriage, which not long ago was the position of Bill and Hillary Clinton and the entire Democratic Party.

Beyond Chick-fil-A, look at the Left's Occupy Wall Street brigades. Here again, there was no edict from Barack Obama or David Axelrod to organize these people. Nonetheless, plenty of incessant Obama demonization of "profits," corporate "jet-owners," nefarious "millionaires and billionaires," big banks, big oil, those not paying their "fair share," and, of course, the monsters on "Wall Street," did the trick. The "progressive" mob sprung into action. In no time, they were marching not only on Wall Street but on front lawns of corporate CEOs -- a very volatile situation.

And then there's the hideous charge that Republicans who oppose mandatory taxpayer funding of abortion somehow thus favor a "war on women." Sandra Fluke has become a liberal heroine for that cultural/political obscenity.

Enough said. On and on it goes. I could give countless examples, some of them personal. We all can. Any conservative can.

In sum, these leftists are Obama's and (more widely) liberalism's willing executioners. They obviously aren't literally executing people -- although that was indeed the literal intent of the Family Research Council gunman -- but they are executing what they believe is a glorious plan for the fundamental transformation of America. They are willingly executing Obama's agenda and their agenda. Any opponents are isolated as enemies and maligned in the most demeaning way. 

And what does this mean? Among other things, it means that liberals really do need to be damned careful about what they're doing here. There are seriously disturbing consequences to their systematic demonization of anyone who disagrees with them. This is becoming truly dangerous. Lives and careers will be destroyed.

Unfortunately, my warning will fall on deaf ears. Being driven by emotion to begin with, and then easily whipped into hysteria, liberals will reject my warning out of hand. After all, in their view, I'm defending the indefensible: vile racists and haters who are loathsome, have no dignity, and deserve to be ruined. On top of that, I'll be lucky if a hundred liberals even read this article and take it seriously.

In short, this country is in really bad shape. The America we knew is gone; it is over. This new breed of leftist is ascendant and angry, and changing the country and the culture in the process. The results are not pretty. Things are only going to get worse.

Dr. Paul Kengor is professor of political science at Grove City College. His latest book is The Communist: Frank Marshall Davis, The Untold Story of Barack Obama's Mentor. His other books include The Crusader: Ronald Reagan and the Fall of Communism and Dupes: How America's Adversaries Have Manipulated Progressives for a Century.