Can the decay and neglect that afflict transportation systems in Minnesota be corrected by a one-time infusion of cash, a drawdown of uncommitted funds and a tighter operation at the Department of Transportation (MnDOT)? Or will a fix require enlarging the state’s transportation revenue stream with increased taxes?

Those questions roughly outline the debate that took shape last week as the 2015 legislative session convened. To their credit, both sides voiced openness to other ideas. But the opening bids by DFL Gov. Mark Dayton and the new state House GOP majority reveal markedly differing notions about what will be required to end the deterioration of the state’s transportation systems, let alone upgrade them to serve a growing population.

The GOP bid announced Thursday relies on repurposing existing funds and adding a bit more, just once. It would call on MnDOT to operate more efficiently and divert an estimated 15 percent savings, or $65 million over two years, to road projects. It would direct that all but 10 percent of roughly $140 million per year that’s “unreserved,” or uncommitted in MnDOT’s budget, be spent exclusively on highway construction and maintenance. That money is currently used to meet a variety of unanticipated needs, including road improvement.

The GOP also would put $200 million of the state’s projected $1 billion surplus in the next two years into local — not state — roads and bridges. That’s roughly equivalent to the cost of one new highway bridge in Greater Minnesota.

Those might be good ideas, but they’re also short-lived and skimpy, adding up, by the GOP tally, to $750 million over four years. That compares with the 2012 recommendation of an expert panel that Minnesota would need to spend $21.2 billion more than existing tax streams will yield over the next 20 years just to sustain the current performance of roads, bridges, rail and transit systems. Improvement would take substantially more.

Dayton’s plan, unveiled Wednesday to an unenthusiastic state Chamber of Commerce audience, also would boost spending by about $750 million — per year, each year for the foreseeable future.

Unlike the GOP proposal, the governor’s plan calls for new tax revenues. He wants to apply the state’s 6.5 percent sales tax to motor fuels and increase license tab fees, which together would add an estimated $485 million per year to the highway trust fund. And he renewed his motion of two years ago for a half-cent sales tax increase in the metro area, dedicated to transit.

Dayton evinced no joy in asking Minnesotans to pay more, and his business audience clearly didn’t like the idea, either. But in an eat-your-spinach tone, he argued that to do otherwise would be less than straight with Minnesotans about the decay that has resulted from 25 years of meager investment.

Since 1988, the Legislature has raised the gas tax once, in 2008, by 8.5 cents per gallon, an amount that was quickly eroded by inflation and consumed by deteriorating infrastructure — particularly bridges.

“There are no easy solutions — only real ones and phony ones,” Dayton said. “I’m open to better solutions, as long as they are real.” On Friday, he faulted the House GOP plan as “a phony solution that will only let things get worse.”

What’s real? We won’t scoff at the potential to improve efficiency or redirect spending at MnDOT. But to build and sustain massive infrastructure and to meet the needs of the whole state, lawmakers won’t “get real” until they look beyond the next two years to the next two decades. Transportation upgrades are many years in the making. The ones Minnesota will need in 2025 and beyond should be in sight now.

It will take new money to pay for them. Those new funds should provide improvements in transit as well as highways and bridges, to serve a changing, aging population. And the money should flow in a reliable, dedicated stream, collected from highway and transit users and protected from the competing demands for the state’s notoriously volatile general fund. That’s been a virtue of the per-gallon gas tax since it was constitutionally dedicated to the state’s trunk highway fund by Minnesota voters in 1924.

The new House transportation committee chair, Rep. Tim Kelly of Red Wing, acknowledged that the bill he unveiled last week is a short-term measure. He told an editorial writer that before the year is over he hopes to consider ways to sustain the state’s transportation system for the longer term. We’ll take that as a hopeful note — and add that Dayton’s proposal is showing the way.