So the natural reaction of the political class is to immediately call for a giant new gas tax. No, really. And it’s not just lefties. Even conservative commentator Charles Krauthammer, who is in most other respects sane and rational, joined in. But at least he was honest about the impetus: “The only time you can even think of proposing a gas tax increase is when oil prices are at rock bottom.”

But of course oil prices fluctuate. It’s hard to say for sure why they are low today or how long they will stay that way. If you can predict that with any kind of certainty, I hope you will invite me to visit your yacht when you make a billion dollars from oil futures. Wait, you mean you’re not going to risk your retirement savings on that bet? Very well, then. Yet that’s what advocates of a gas tax increase always do: ask us to bet that because we can supposedly afford a little extra money today, we should enact a new tax that will last forever.

But don’t bother to examine this particular folly. You can understand it only if you understand that in some minds there is a constant imperative for the expansion of government. The only question they ask is whether they can get away with it. When gas prices are low, they think they can, so that is what they advocate. But the tax itself is not a considered economic measure or a means to some other end. It is an article of faith and an end in itself, because government is an article of faith and an end in itself.