In the days before the “hook-up” culture started teaching all women of every age to act like teenage boys, there was an ugly expression which callous men used: Some girls were “cheap dates.” They were so flattered when men showed interest in them, that they would respond by giving a sexually aggressive guy what he wanted, in the hope that he’d keep calling them, maybe even fall in love. He rarely did.

No doubt many girls who let themselves be treated as “cheap dates” were in fact quite attractive, intelligent, compassionate and kind. They had a lot more to offer a man than a forgettable roll in the hay, if only they had known it.

Well, there’s a political philosophy out there that persistently acts like that lonely teenage girl with low self-esteem. It’s called libertarianism. Maybe you’ve heard of it.

In its most defensible form, the libertarian worldview has a certain stark, even classical beauty — like a Greek statue seen at sunrise. Its fundamental premise is the dignity of the person and his right not to suffer violence or coercion. From this flows the “non-violence” principle: In our interactions with others, we will not use force or fraud but free exchange. All we ask of them in return is exactly the same.

We are each finally responsible for our own lives and our choices, and we should neither be parasitical on other human beings nor permit them to prey on us. We should not blame our problems on a nebulous “society,” nor let envy goad us into finding easy scapegoats, such as “the One Percent,” or “the WASPs” or “the Jews.” Nor should we expect the state to act as our wet nurse, concierge  or hired hit man.

The State is there, if at all, to keep all bandits and invaders at bay. We don’t want it to wipe our nose, and we won’t let it steal our handkerchief. Like pioneers on the frontier or settlers on Mars ((libertarians love both Westerns and science fiction)  we start off life with a nearly blank slate, and must carve out our way in the wilderness.

It’s incomplete, but there is much truth in this vision. The State has proven dangerous throughout history — especially in the 20^th century, when apart from all deaths in wars, some 170 million civilians were murdered by their governments. Even apart from totalitarianism and murderous war, there are much worse mistakes we could make than to prune the invasive, toxic weed of unlimited government, which grows like kudzu in every nook and cranny of our lives, strangling human initiative and transforming capable grown-ups into lazy, resentful drones.

No, I don’t mean inner-city teenage moms, who are mostly victims of the welfare state — which rewards them with subsidies and financial independence for getting pregnant at age 16. I’m referring to the thousands of white, college-educated liberal arts grads using food stamps at Whole Foods, teaching adjunct as a hobby, and blogging all day about “sustainability.” Such people should go work at some place like Hobby Lobby. In a libertarian society, hunger, if nothing else, would compel them to do so.

A libertarian society would also starve the crony capitalists, who cynically exploit programs like farm subsidies to rake in tens of billions in unearned profits on useless goods — enough corn to choke us, overpriced cotton protected by tariffs that harm poor farmers in Africa, even government-subsidized tobacco. Many corporations, with thousands of lobbyists on their payroll, are tapeworms on the taxpayer, using the State to suppress competitors so that they can fleece consumers. And don’t get libertarians started on defense companies, NSA spies or the prisoners of our Drug War.

So for all their lovely principles, and cogent policy insights, why do libertarians let themselves be used again and again by the left? Like a gorgeous National Merit Scholar with an unhealthy taste for “bad boys,” libertarians consistently see their ideas trotted out whenever it suits progressives who wish to bulldoze some bulwark of ordered liberty — then callously discarded, in favor of bigger and badder government. Here are just three examples.

Same-Sex Marriage

Libertarians defend freedom of contract and free association, and the Left made good use of their arguments in attacking natural marriage. By the same principle, “covenant marriages” should also be legal and enforceable — but is anyone arguing for that? Far worse, if the Supreme Court mutilates marriage, Obama’s solicitor general has warned us that the whole panoply of anti-discrimination laws will be used to target churches that won’t worship Caesar. So big government grows, private schools and charities close, Christians lose their liberty, and the left moves on to the next target of opportunity.

Open Borders

Most libertarians argue for the free movement of peoples, and favor open borders. They say that absent a welfare state, people would spontaneously seek out opportunities, then when jobs dried up they would pick up and leave. Maybe this is true. But we will never find out because the welfare state isn’t going anywhere — in part because recent immigrants are heavy users of public benefits, so they almost universally vote for Democrats who will extend them. And impose onerous regulations on employers, nullifying their freedom of contract. And raise taxes. Low-skill immigrants serve the left as captive voters, undermining almost everything libertarians say they stand for. The left uses libertarians as human shears to cut holes in the border fence, then drops them and moves along.

Islam and War

Libertarians are right to be reflexively antiwar, since war really is “the health of the state.” Each major war we have fought, needful or not, greased the massive and irreversible growth of bureaucratic control over American citizens’ lives. Libertarians were wise when they warned that building liberal democracy via cluster bomb in the Muslim world is a wasteful errand. They are even right to worry about the implications of seeding mosques with FBI agents and informants.

But libertarians are dead wrong when they try to whitewash Islam, to pooh-pooh truth-tellers who point to that religion’s core texts, as interpreted by all recognized Islamic scholars. Their message is icy cold and crystal clear: Islam is a religion of power, of social control, which respects no rights but Allah’s. Human beings are “slaves of God,” and non-Muslims or bad Muslims are rebellious slaves who need to be punished. Devout Muslims are called to punish them, via jihad, terror, or honor-killing.

Every country on earth is a target for infiltration and conquest, then the absolute suppression of every worldview except Islam. The Muslim utopia is something like Saudi Arabia or the Islamic state. They will build it here if we let them. But libertarians encourage open immigration, which brings in millions of Muslims, a certain percentage of whom will wage jihad. Acts of terror give spooks and spies in the NSA a pretext to listen to our calls and hack our email accounts. Big government grows again, with the unwitting help of libertarian efforts to shrink it.

Used and then Discarded

If only libertarians had more respect for the integrity of their principles, and would stop letting themselves be used by opportunistic progressives. On any given issue, there are valid small-government, individual-liberties arguments to be made. But liberties come with responsibilities, which is something the left won’t admit.

So the left will gleefully accept libertarian support in removing some traditionalist or conservative restriction on individual freedom. But they won’t agree that people must live with the consequences of their choices. You want a same-sex marriage, fine — but don’t expect the Catholics or Baptists to accept it or perform it — so a libertarian would say. The leftist drops the liberty argument the moment he’s finished with it, and demands that the state enforce acceptance from every citizen.

You want to come work in America? Fine, but if you can’t support yourself you have to leave. Again, the left stops feigning interest in freedom the moment the border is open, and welcomes every immigrant to his crib in the nanny state. The process is drearily predictable.

Too many libertarians are eager to support leftist attacks on order, confident that in its absence, liberty will grow. But time and time again we see what springs up instead: More coercion, of a streamlined, more poisonous modern strain.

I wish libertarians could learn to love their principles more. I wish I could take each one of them aside and say, “You’re fabulous. You’re special!  Don’t sell yourself so cheaply. Hold out for that wedding ring, and stay away from those creepy guys with goatees in the Che Guevara t-shirts.”