Gov. Mark Dayton gave Minnesota a much-needed infrastructure boost and the 2018 legislative session a measure of redemption Wednesday when he signed into law a $1.46 billion bonding bill — the only one of the year’s three major bills to pass his muster.

The green light the DFL governor gave to all but $1 million in the public works bill was a welcome sight in many places throughout the state, particularly since it was by no means assured. Though Dayton’s own proposed bonding bill was only slightly larger in total, it differed significantly from the version sent to his desk by bipartisan majorities in the Republican-controlled Legislature. Dayton’s complaints about the bill filled a four-page letter.

His critique deserves notice. This bonding bill, which took its final form with only hours to spare in the session, contains several features that could set undesirable precedents. For example, $25 million for school safety grants is drawn not from the general fund but from the state’s reserve fund. That fund should not be tapped while the state’s books are in the black, as was the case this year.

Similarly ill-advised is the bill’s use of the lottery-fueled Environmental Trust Fund to finance $98 million in projects with appropriation bonds, a financing instrument that typically carries an interest rate 0.5 percent to 1 percent higher than a general obligation bond. That makes it hardly a frugal choice — but perversely, it was done to keep new general obligation debt at $825 million, a threshold Republican legislators saw as conservative. The move will obligate the fund to debt service, thereby constricting its annual outlays for environmental improvement projects. That raises the potential for a lawsuit challenging this new use of the constitutionally dedicated fund.

The bonding bill also became a vehicle for policy measures that Dayton said he would have vetoed had they come to him as free-standing bills. Several of them had little or no public hearing. The bundling of controversial measures in this fashion led last week to Dayton’s veto of a massive budget bill. With the bonding bill, he said, his desire for infrastructure improvements outweighed his objections to the bill’s policy measures. We agree with that call. But it will be a blow to lawmaking accountability if bonding bills become “garbage bills” in years to come.

The Legislature this year opted repeatedly to test the sincerity of Dayton’s veto threats rather than negotiate with him to find middle ground. The result has been a flurry of vetoes. Four more came Wednesday: for Metropolitan Council reorganization; an unfunded revamp of the motor vehicle licensure system; additional penalties for those involved in pipeline protests; and removal from the Minnesota Pollution Control Agency of the authority to set a wild rice water standard.

With the opportunity for negotiation now past, Dayton made the right call. But Minnesota would have been better served if that opportunity had been seized.