The first big-money ballot measure to qualify for the 2018 ballot was certified by the secretary of state's Elections Division this week.

What will soon be known as Measure 103 is backed by large grocery chains and would amend the Oregon Constitution to permanently prohibit the imposition of a tax "upon the sale or distribution of groceries."

The prohibition would be the first of its kind nationally but would not include taxes on alcohol, tobacco or marijuana. It would include sodas and other sugary drinks that are now being taxed in Seattle, Oakland and many other cities and have been the subject of a long-planned but never-executed Multnomah County tax.

The measure would also freeze in place the state's corporate minimum tax, a provision that adds to progressives' hostility to it.

Mary King, a retired Portland State University economics professor who's looked at the measure, said it's "a massive, unprecedented carve-out for some of the biggest retailers in the world that will apply to far more than just the food they sell."