A campaign in Oregon is being bitterly fought, with vast sums spent by both sides on TV and other ads, even more money than for the governor's race.

The titanic tussle is over a proposed tax that is supposed to apply to companies making the most sales in the state, but opponents say every Oregonian will be affected.

Both sides have arrayed armies of experts who say the tax on companies' sales of more than $25 million will trigger a rise in prices, or that such a scenario is bogus. The assessments differ depending on whether the well-heeled campaigns are for or against Measure 97.

Oregon is one of five states in America that doesn't have sales taxes. Oregonians have rejected sales tax proposals nine times in nearly 90 years.