Former New York City Mayor Michael Bloomberg has again waded into Oregon politics with a record-breaking, $1.5 million contribution to fight Measure 103, an initiative that would prohibit taxes on grocery revenue and most items sold in the supermarkets.

Bloomberg did not explain the reason for the mammoth contribution, disclosed Friday. As New York City mayor, though, Bloomberg unsuccessfully sought to ban super-sized sodas. And in 2017 he spent $5 million in support of a proposed soda tax in Chicago.

While Measure 103 is nominally about a ban on taxing groceries and grocers, The Oregonian/OregonLive reported earlier this month that it's focused in large part on establishing a constitutional prohibition on soda taxes statewide.

Even before Bloomberg's money arrived, leading contributors for and against Measure 103 were partisans in the national fight over soda taxes. Willamette Week, which first noted Bloomberg's contribution, said it's the largest individual political donation in Oregon history.

Oregon has no general food tax and -- Measure 103 notwithstanding -- no one is seriously contemplating establishing such a thing. The state has no soda taxes, either, but advocates considered proposing one in Multnomah County last year. In other parts of the country, cities that have soda taxes have experienced a marked drop in sales.

Advocates of soda taxes believe they could help curb Americans' appetites for an unhealthy beverage while generating revenue for health programs or other public policy goals.

To groceries, though, sodas are a leading profit center. They generate big sales and the soda industry pays retailers directly to give beverages prominent placement inside stores.

What it would do

: A constitutional amendment prohibiting new taxes on grocers and most groceries – including food and soda.

What it wouldn't do

: The ballot measure would still allow new taxes on alcohol, marijuana and tobacco, and increases in grocers’ corporate income taxes.

What it might do

: Opponents and critics disagree about the meaning of the language in the ballot measure. Critics say the initiative might ban taxes on restaurants and food served to patients in hospitals and possibly bar taxes on e-cigarettes. It might also apply to the cost of transporting food and could bar further increases in bottle and can deposits.

What it would cost

: Public agencies wouldn’t lose any current revenue because Measure 103 doesn’t repeal any taxes. But it would reduce options for future revenue.

Measure 103's supporters have raised nearly $5.3 million for their campaign, led by the beverage industry and grocery chains. Bloomberg's contribution brings the total raised to fight the initiative to almost $2.7 million, led by other soda tax proponents and public sector unions.

Recent polls show Measure 103 trailing.

The initiative's backers said Bloomberg's involvement reflects his policy goals, which include taxing unhealthy products such as sugary drinks to reduce their consumption.

"Mr. Bloomberg's money and words are proof positive that Oregonian's groceries are targeted for new taxes. Now more than ever we need YES on Measure 103 to keep our groceries tax free," said Joe Gilliam, president of the NW Grocery Association.

Bloomberg did not respond to a request for comment but opponents of Measure 103 issued a statement welcoming him to their fight: "We are honored by all the local and national support we've received to fight Measure 103."

Bloomberg, of course, is not the only billionaire using his money to influence the outcome of Oregon's general election. Nike co-founder Phil Knight has given $2.5 million to support Republican Knute Buehler's campaign for governor, and Knight gave another $1 million to the Republican Governors' Association, which has in turn contributed to Buehler's campaign.

-- Mike Rogoway | twitter: @rogoway | 503-294-7699