The text of Measure 97, the proposed $3 billion corporate tax increase on the November ballot, says that new revenue raised "shall be used," for education, health care and services for senior citizens.

In legalese, "shall" means must.

But now the Legislature's leading tax expert says this earmarking of new revenue may not be allowed.

That's because the Oregon constitution requires that taxes generated from motor vehicle fuels must flow into the state Highway Fund and can only be used for transportation projects.

And although it is unclear exactly which companies Measure 97 would affect and how much they would pay if the measure passes, it's a safe bet that some of the money—a 2.5 percent tax on the Oregon sales of of C corporations exceeding $25 million—would come from companies selling gasoline and diesel fuel.

Paul Warner, the director of the state's Legislative Revenue Office, is responsible for analyzing the impact Measure 97 would have on the state's finances.

Warner says that contrary to the language of Measure 97, any new tax receipts generated from corporations' sale of motor-vehicle fuels would probably go to the Highway Fund—and not to the state's general fund.

"We do think there is a good chance that gross receipts from fuel sales by corporations (Safeway or Fred Meyer for example) would be dedicated to the highway fund," Warner tells WW via email.

The section of the Oregon constitution that relates to transportation taxes is broad and somewhat ambiguous. Article IX, section 3a of the Oregon constitution also dedicates to transportation revenue raised from another source that could be impacted by Measure 97: "any tax or excise levied on the ownership, operation or use of motor vehicles."

That clause raises the question of whether new taxes paid by car, truck, bus, motorcycle and RV dealers would also be dedicated to transportation funding.

Warner has asked the Legislature's lawyers for guidance on that issue.

"We are uncertain how broad the dedication [to the Highway Fund] would be," he says. "Legislative Counsel is looking into the question and hopefully will have something definitive soon."

Meanwhile, auto dealers have been among the most generous contributors so far to the "no" on Measure 97 campaign, called Defeat the Tax on Oregon Sales. The Automobile Dealers Association of Portland has given $250,000; the Oregon Automobile Dealers Association, $170,000; and publicly-traded Lithia Motors, $150,000.

Katherine Driessen, a spokeswoman for A Better Oregon, the group behind Measure 97, acknowledges that if the measure passes, some of the money could go to uses other than specified by the ballot measure.

"We've heard estimates of about $100 million annually," Driessen says. "Assuming about $100 million is redirected, the fiscal impact of investing in education, healthcare and senior services will be small."

That estimate—$100 million—is a lot of money, but only about 3 percent of what Measure 97 is projected to raise annually. Until there's a clear interpretation of the constitutional set-aside to the Highway Fund, however, it's only a guess.

Transportation funding in its own right is a hot button issue.

The Oregon Department of Transportation is heavily burdened with debt and gas tax revenue is insufficient to pay for the projects the agency wants to tackle. In 2015, a $343 million transportation funding package collapsed late in the legislative session and lawmakers from both parties have barnstormed the state since, seeking to build support for funding in 2017. Measure 97 could complicate that effort.

Warner says he expects to receive legal guidance soon on exactly which Measure 97 revenues would flow into the Highway Fund.

"That is the question–how broadly would the dedication [to transportation] be defined," Warner says. "For us, once we have legal direction on that, we will can produce an estimated revenue impact on the Highway Fund—though there will be data issues to work through."