I spent the better part of Thursday evening on my front porch, eating fried chicken and birthday cake (my older son turned 11) and talking politics with a close friend of the family who happens to be an inveterate leftie. Good times, although such conversation took its usual course — a mixture of bon mot, sarcastic repartee, and earnest attempt to persuade each other on matters of core conviction.

At some point, the talk turned to Afghanistan, and I was surprised to find that my friend — far enough “left” that he was a reluctant, rather than enthusiastic, Obama voter last year — is reconsidering that war.

Like most Americans, he had apparently, if grudgingly, approved of the initial purported mission (the liquidation of al Qaeda), even if he considered 9/11 and its aftermath a regrettable case of preventable “blowback” of the type which should be avoided in the future. Although we hadn’t discussed it in some time, I’d been under the general impression that once that mission gave way to “nation-building,” he wasn’t very enthused about it. At least he didn’t seem very up on it during the reign of The Despicable Dubyah (the bumper sticker on his van used to read “Impeach Bush;” now “impeach” has been crossed out and replaced with “hang”).

Now, though, he has humanitarian concerns in mind: Whether or not Afghanistan will slip back into Islamist tyranny if the US and other occupying forces leave it to its own devices. He didn’t express great certainty on the point, but he related it to Darfur, another hot spot where he does believe the US should intervene, if necessary militarily, to put a stop to tyranny and mass murder. Funny what regime change does to some people.

That topic of conversation went away almost immediately after my reply, although that may have been less due to the force of my argument than to the attractions of the chicken, the cake, or the other available conversations (he argued the virtues of planning and zoning with my 8-year-old son, who’s growing into a reasonably sophisticated anarchist without a whole lot of tutoring from Dad, and who wants to build a video game store in our front yard).

The tenor of my reply was to the following effect: I’ll be more than happy to stand aside and let the Department of Defense intervene in Afghanistan, Darfur, wherever … just as soon as they’re willing to raise the money for such interventions with bake sales, door-to-door subscription drives, etc., and just as long as they’re not committing crimes at the delivery end of their interventions.

As long as they’re stealing the money to do whatever it is they do, then they’re possessed of neither an incentive to do the right things nor the legitimacy to do anything at all.

And even if they convert to voluntary financing, they’re legit only insofar as they operate within the baseline human ethical constraint — namely, renunciation of, and acceptance of liability for, the use of force against anyone who has not first initiated force.

If anything defines the consensus in which a moral society can flower and thrive, it’s the recognition that theft, murder and other initiations of force place those who commit them outside of said society and in opposition to it. If there’s any basis in fact whatsoever for the idea of a “social contract,” it’s that: You only get to be part of society if you keep your hands out of other people’s pockets and off other people’s throats.

Yet theft and murder constitute the two points on any chart of behaviors which a plot of the state’s operations must inevitably cross. The state sustains itself through acts of theft and enforces its writ through the threat of death. If it doesn’t do those two things, it’s not a state. If it does do those two things, its existence and operations are inimical to the existence of the kind of society we’re frequently told can’t exist without it.

Hobbes was wrong. We can have the state or we can have the social contract. We can’t have both.

Translations for this article:

• Spanish, El Estado contra el contrato social.