A gas tax won’t end dependence on foreign oil, but that’s OK.

And there's another environmental problem we're avoiding facing in our visions of the greener, oil-free future: When all this electric-vehicle mobility comes online, we'll still have to burn coal to provide the juice. Or ramp up our nuclear power capacity. Or hope that prohibitively expensive wind and solar will somehow suddenly become more cost-effective.

So we're looking at running the transportation grid largely on gasoline for the next 50 years. Depending on how you feel about peak oil—the theory that global oil production has "peaked" (or will peak soon) and that it will only decline from here until we exhaust the planet's supply—a gas tax now means both acknowledging and stretching out a limited supply. And that's not necessarily a green disaster, because the progressive improvement of emission-control technologies has reduced the environmental damage that the internal combustion engine inflicts. If you buy a run-of-the-mill Honda Civic tomorrow—not even a hybrid—it will have significantly lower emissions than the same model produced 10 years ago.

Even so, a gas tax is an idea whose time has most definitely come, considering that some version has been on the political table at least since John Anderson's 1980 presidential campaign. Various schemes have been proposed. The gradualist left, sensing an opportunity to shift consumers toward greener vehicles, favors adding a few cents every year. This would yield a modest, phased uptick in the current tax, which at 18.4 cents per gallon hasn't been raised since 1993.

On the right, some are calling for a "net zero" gas tax, in which any hike in the price of gas is offset by a cut in payroll taxes. The goal here is to influence consumer behavior and automaker engineering, but also to prevent the greedy federal government from seeing any revenue increase.

Others have been more aggressive, demanding that we seize this historic opportunity to establish a benchmark price per gallon that mirrors $100-per-barrel oil. (I count myself in this camp, although I don't think we should be taxing gas at all for the next year—in fact, I think we should be doing whatever we can to make gas cheaper so that Detroit can sell high-profit, low-mileage trucks and SUVs to generate enough cash to enable meaningful long-term restructuring, then move toward sustainable vehicles.)

Objectors have pointed out that gas has been taxed up the wazoo in Europe but that income increases were leading to more car ownership and more driving than ever before. Just as in the United States, affluence allows for consumers to absorb even high rates of taxation.