The latest Vermont political commercial — the one featuring a Sue Minter bobblehead with exposure of how often she has supported raising the cost of driving a car — evokes five reactions, four of which are not very important.

The least important of all is that as a state senator, Phil Scott at least once voted for a bill that would increase gasoline taxes. Perhaps that’s because he’s a responsible public official.

Next least important is that the ad — a product of the Republican Governors Association — is factually accurate. In addition to supporting gas tax increases, Minter did sponsor legislation that would have imposed a stiff fine on a motorist leaving his or her car idling, and another imposing a per-mile tax on driving.

Slightly more important is that “factually accurate” does not always means “intellectually honest,” and this ad is a good example.

Neither of those bills (one of which had a Republican co-sponsor) went anywhere. It’s likely that neither was intended to go anywhere. Lawmakers often propose bills to start a conversation, to gauge how much support there might be for a general concept, not to pass the specific piece of legislation.

Or to shut up a vocal constituency that is pressuring the legislator to “do something” about whatever is galling the vocal constituents.

These bills appear to have been inspired by one or both of those stimuli. Otherwise, the sponsors would have bugged the committee chairs at least to hold hearings on the proposals. No such hearings were held.

Before getting too inflamed over the sleight-of-hand of the Republican Governors Association, though, (here is the last of the unimportant reactions) consider that it has been matched of late by comparable sneakiness by … wait for it … the Democratic Governors Association.

Its recent ad on Minter’s behalf said Scott “even wanted to put a state board in charge of local school budgets.”

Oh, come on. A couple of years ago Scott speculated that, just as the Green Mountain Care Board regulates hospital costs, perhaps a nonpolitical central board could ride herd on school spending. It wasn’t a very good idea, but it wasn’t a proposal. It was musing, sort of like Minter and the per-mile tax. Candidates ought to be able to muse freely, without worrying that some political opponent will make much out of little later on. A politician who fears to muse will never come up with a good idea.

Now for the fifth reaction, the one that is important: Minter was right.

Oh, not necessarily in seeking a fine for folks who leave their car idling or in a per-mile fee (which usually replaces the gasoline tax). The wisdom of these details is open to debate.

But right on the larger issue: Americans (and that would include Vermonters) should be charged more for driving their cars. As it is, every auto trip is government-subsidized, every driver and passenger a welfare recipient. America’s automobile transportation system is a perverse form of socialism under which everybody — including the many who rarely or never ride in cars — is taxed so the drivers and their passengers can ride around without paying the full cost of their trips.

If they did pay the full cost, gasoline taxes would be double or quadruple the combined federal 43.3 cents per gallon Vermonters now pay. We know this because it is double or quadruple that in other countries. Just north of the border in La Belle Province de Quebec, motorists pay the equivalent of $1.31 a gallon. Across the sea in Jolly Old England, they pay $2.84 per gallon plus a 20 percent value added tax on the combined price and tax.

In those countries, then, motorists may come close to paying the full cost of building, maintaining, patrolling and managing their highway systems. American motorists do not. Yes, there are gasoline excise taxes, registration fees and traffic violation fines. They help. But the full cost of providing our auto transportation system far exceeds those revenues.

By exactly how much is hard to determine. A recent study by the Frontier Group, based on an analysis of federal data, concluded that so-called user fee revenues “pay only about half the cost of building and maintaining the nation’s network of highways, roads and streets.”

Since 1947, the Frontier study found, “the amount of money spent on highways, roads and streets has exceeded the amount raised through gasoline taxes and other so-called ‘user fees’ by $600 billion (in constant, 2005 dollars), representing a massive transfer of general government funds to highways.”

But this no doubt understates the extent of the taxpayer subsidy to driving. It does not include the several billion dollars in annual tax-preference subsidies to the oil industry. It does not include the health care costs of treating people sickened by auto pollution or injured in auto accidents. It does not include the cost of allowing businesses and self-employed individuals to write down the cost of cars and trucks they own.

And it does not include what UCLA professor Donald Shoup called “the high cost of free parking.” Endorsing Shoup’s analysis, conservative economist Tyler Cowen wrote that “the presence of so many (free) parking spaces is an artifact of regulation and serves as a powerful subsidy to cars and car trips.”

Like other cities around the country, Burlington is beginning to recognize this and is modernizing its parking meter system. But dozens of smaller Vermont cities and towns still offer free parking, not only along the curb but in town-maintained parking lots.

At least as seen by the Agency of Transportation, Vermont subsidizes auto use less than some other states. Jacqueline LeBlanc, the marketing and outreach coordinator for the agency, said gasoline tax revenue finances “every activity that VTrans undertakes, including maintenance, DMV, paving, roadway projects … traffic lights, line painting.” In addition, “significant amounts go toward funding the municipal highway system (and) bike and pedestrian facilities.”

But those “significant amounts” do not cover all local road maintenance costs. The snowplow keeping a country road passable in winter operates thanks to local taxes.

Taken together, all these subsidies constitute a form of national economic planning, creating incentives for more suburban development, more sprawl, more shopping malls. The elected officials who agree that driving a car should be more expensive (and that might include both candidates for governor) should be praised, not scorned.

Jon Margolis is VTDigger’s political columnist.