Few characteristics unite Maryland, New Mexico and Missouri under the same umbrella. Maryland has a land mass less than one-tenth of New Mexico’s and a median household income that’s 50 percent higher. Missouri’s income and size, like its geography, put it near the mid-point between the other two states.

What the three states do have in common is Pete Rahn. Maryland’s secretary of transportation since January, Rahn was director of the Missouri Department of Transportation from 2004 to 2010 and was cabinet secretary of the New Mexico State Highway and Transportation Department from 1995 to 2002.

He is better placed than most to know first-hand why state officials — regardless of which party is in power — say Washington must play a big role in transportation. The alternative is an uneven, and inadequate, transportation network, he says.

“Even if you have enlightened states who are willing to raise funds  . . .  we can’t function nationally with islands of good transportation in a sea of mediocre or poor,” Rahn said in a telephone interview. “We have to have a national transportation program. It has to be a nationally funded and nationally invested program.”

States are differently equipped to respond when Congress opts for short-term highway extensions or reduces funding. The states rely differently on the federal government to support their own transportation spending.

Of the three states on his resume, Rahn says Maryland, receiving just below 20 percent of its funds from the federal government, would be best able to cope without the money. “That doesn’t mean it wouldn’t cause real pain.” The federal money goes to places where the public would instantly notice a drop, he said.

New Mexico issues bonds to cover capital projects, relying on as much as one third of federal aid to back bonds that can run as long as 20 years. New Mexico received 47 percent of its 2014 transportation budget from the federal government. Missouri relies on matching federal aid, getting 43 percent of its 2014 transportation budget from Washington.

“The reality is, islands of good transportation in a sea of mediocre will drive businesses to make different decisions about where they want to invest,” Rahn says. “It is not good for us as a country to have decisions devolve to that level.”

Somebody in Iowa must have the same opportunity as somebody on the coast of Florida to get access to markets, he says. “That cannot be done without a national transportation program.”

States that can afford to invest in transportation infrastructure can’t ignore what’s going on in neighboring states that can’t. Rahn notes, for example, that moving goods between California and Texas, the states with the two biggest economies, requires using New Mexico’s roads.

“The transportation system is the foundation system for economic development,” he says. “If you don’t have the transportation system, you aren’t going to have economic development…. The loss would be significant to any state.”

Rahn has little time for those who argue that states are stepping up to fill the gap left by Congress. “I’ve certainly seen opinion pieces that transportation is solving its own problems because states are stepping up,” he says. “I don’t see how anyone can draw that conclusion.”

Some states are increasing spending, but that returns to the problem of islands of good transportation, he says. Rahn nevertheless is optimistic that Congress will eventually do what transportation officials around the country say is needed.

“If we keep kicking this can down the road, eventually it’s going to be a gravel road they are kicking the can down,” he says. “The pain of inaction will eventually be greater than the pain of action.”

This piece originally appeared as part of the cover story of the April 20 CQ Weekly.