Correction: An earlier version of this editorial incorrectlyreported that Gov. Robert F. McDonnell has never signed Grover Norquist’s anti-tax pledge. Mr. McDonnell signed such a pledge in 2002, although he now says he is not “a current signer” of the pledge. The following version has been corrected.

UNLIKE MANY of his fellow Republicans, Virginia Gov. Robert F. McDonnell has said plainly for years that funding for his state’s rickety transportation network is inadequate and unsustainable. He also recognizes that reality precludes raiding other core functions of government — education, public safety, health care — to build roads; Democrats are united against that strategy, and more than a few Republicans oppose it, too. But even as he enters his last year in office, it remains unclear whether Mr. McDonnell has the spine to tackle what he often acknowledges is the commonwealth’s most urgent unmet need: a transportation-funding system in the process of collapse.

To fix it would require him to challenge many of his own party’s backbenchers. And it would force him to confront GOP orthodoxy in Richmond, which cannot countenance raising new revenue for any purpose — even if the revenue is essential to Virginia’s economy. Does Mr. McDonnell, who may have presidential ambitions in 2016, have the stomach for the fight?

As Virginians wait to discover what the governor will propose ahead of the legislative session starting next month, the cost of inaction is clear. In four years, the state will have no money to devote to any new road, rail or bridge construction. That’s right, zero. At current trends, every available dollar will be sponged up just to repair and maintain existing infrastructure. And if the state’s road-building money dries up, so do millions in federal matching funds.

In the face of that hard reality, Mr. McDonnell says he is crafting a package that would yield $500 million annually in new revenue for transportation. The amount is modest — the state probably needs twice that much — but it’s something. Yet the governor has not explained how he would find the money other than to publicly float the idea of indexing the gasoline tax to inflation, a measure he’s toyed with for years.

That trial balloon was predictably scorned by Grover Norquist, the anti-tax maven, who warned Virginia lawmakers Monday that it would be “a job-killing tax increase.” That’s absurd. Taxes on sales and income rise along with prices and salaries. So why should the state’s gas tax, fixed at 17.5 cents per gallon since 1986 (when gas cost 93 cents a gallon), remain unchanged, its purchasing power shriveling as highways crumble, construction prices rise and cars become more fuel-efficient?

Mr. Norquist is entitled to his magical thinking. But when he uses it to try to intimidate Virginia lawmakers, Mr. McDonnell must push back. On Tuesday, the governor dispatched two high-ranking aides to meet with Mr. Norquist. The upshot of that conversation remains unknown.

Mr. McDonnell has signed Mr. Norquist’s blanket anti-tax pledge but, unlike several dozen Republican lawmakers in Richmond who’ve also done so, he now says that he is not “a current signer” of the pledge. That’s different, however, from mustering the will to challenge the no-tax theology head-on. If Mr. McDonnell wants to avoid kicking the can down Virginia’s buckling roads, he’ll have to do so.