Oregon's richest man said he would do whatever he could to end Democrats' 40-year hold on the state and prevent its nominee Tina Kotek winning the race to be the next governor.

Last week, Phil Knight, the billionaire co-founder of Nike, donated $1 million to Republican candidate Christine Drazan after bankrolling the campaign of an independent who has turned the election into a toss-up.

Analysts said his two-horse strategy suggested Knight was intent on keeping the Democrat out of the governor's mansion.

A swath of the electorate in this liberal state has turned on the outgoing Democratic governor, blaming her for woke policies that have allowed an explosion of crime, drug use and homelessness. 

In a rare interview, Knight, 84, said he would do whatever it took to end the Democrat's stranglehold on power and described himself as 'an anti-Tina person.'

'One of the political cartoons after our legislative session had a person snorting cocaine out of a mountain of white,' he told the New York Times. 

'It said, "Which of these is illegal in Oregon?" And the answer was the plastic straw.'

Before that, he had given $3.75 million to Betsy Johnson, running as an independent. 

His money has turned the race into a close-fought contest.