The Republican presidential candidates were mostly silent on transportation funding issues in their fourth debate on Tuesday night, as Congress grapples with an Nov. 20 deadline for extending the nation's infrastructure funding.
Only one of the eight candidates in the main debate on Fox Business Network — front-runner Donald TrumpDonald TrumpSix big off-year elections you might be missing Twitter suspends GOP Rep. Banks for misgendering trans health official Meghan McCain to Trump: 'Thanks for the publicity' MORE (R) — made even a passing reference to rebuilding the nation's infrastructure in their two hour debate in Wisconsin.
But even Trump steered clear of offering specific proposals for paying for new transportation projects.
"We have to get smart. We can't continue to be the policeman of the world. We are $19 trillion dollars in debt, we have a country that's going to hell, we have an infrastructure that's falling apart," Trump said during a debate about potential interventions in standoffs with foreign nations like Russia.
"Our roads, our bridges, our schools, our airports and we have to start investing money in our country," he continued.
Former Pennslyvania Sen. Rick Santorum (R) offered more specifics in an earlier undercard debate on Tuesday evening, endorsing a plan to sharply reduce federal gas taxes and transfer responsibility for road building to state governments.
"We need to get the federal government out of this infrastructure business, other than vital economic highways," Santorum said in response to a question about raising the gas tax to pay for road projects.
"It has been said that if we cut the gas tax to 3 to 5 cents and send the rest back to the states, and just take care of the federal infrastructure that's vital for our economy...we don't need the federal government in the road business that it is today," he continued of the plan to sharply cut back the gas tax, which is known as "devolution."
The proposal to sharply reduce the gas tax is popular with staunch conservatives, who argue that development of road and transit infrastructure should be left up to states. Transportation advocates have resisted the concept of rolling back the gas tax, however.
Most devolution proposals typically call for reducing the gas tax to 3.7 cents per gallon and replacing current congressional appropriations with block grants that states would compete for.
The lack of focus on concrete transportation funding proposals from GOP presidential candidates other than Trump and Santorum comes as Congress is struggling to come up with a way to pay for an infrastructure funding extension that is set to expire on Nov. 20.
Transportation advocates complain that Congress has not passed an infrastructure measure that lasts longer than two years since 2005 due to a highway funding shortfall that is estimated to be $16 billion annually.
The traditional source for transportation funding is revenue that is collected by the federal gas tax, which is currently set at 18.4 cents per gallon. The gas tax brings about $34 billion per year, but the federal government typically spends about $50 billion annually on transportation projects.
Transportation advocates have pushed for a gas tax increase to help make up the difference, but Republicans have been reluctant to ask drivers to pay more at the pump.
Trump has spotlighted transportation funding issues before, notably making critical remarks about New York's LaGuardia Airport.
"You go over to Qatar, you go over to Saudia Arabia, you go over to some of these countries — China — and you see airports like you've never, ever seen before," he said during during a campaign event in New Hampshire in September.
"Then you come back and you land at LaGuardia ... or Newark or LAX and you walk into a filthy terminal that is falling apart and you have broken terrazzo floors and that's all you have."
Trump's comments about LaGuardia were part of a broader call for more infrastructure investment, although he did not get specific then or during Tuesday's debate how he would pay for the new road projects.
"I want to rebuild this country," the GOP presidential front-runner said during his earlier campaign appearance.
"We have bridges that are falling down," Trump continued. "We have 60 percent of our bridges in danger. We have roadways that are coming part. We have airports that are third world. ... We have to rebuild our own country.
The other GOP candidates in Tuesday's debate focused on broader economic issues such as taxes and regulation and foreign policy.
-This post was updated with new information at 1:48 p.m.