A new statewide poll shows Democratic presidential nominee Hillary Rodham Clinton is all but a lock to win Oregon, holding a 13-point lead over Republican nominee Donald J. Trump.

But the survey, conducted this week by Davis Hibbitts and Midghall, shows more than a third of the registered voters surveyed are planning to vote for a third-party candidate, haven't made up their minds or don't plan to vote in the presidential race at all.

"If there is a shocker in this survey, it's the utter weakness of the two presidential candidates," says John Horvick, vice president and political director of DHM Research. "Oregon is known for its high voter turnout, but we'll be watching to see if this lack of enthusiasm starts to affect participation and down ballot races."

The phone survey, the first conducted in several months in Oregon, shows Clinton with a commanding lead over Trump, 38 percent to 25 percent. But Trump is running even with Clinton outside the Portland metro area.

And with the presidential race a year old and less than two months until election day, nearly 38 percent of registered voters don't support either Clinton or Trump.

Libertarian Party candidate Gary Johnson has the support of 10 percent of registered voters, and Green Party candidate Jill Stein gets 3 percent. Another 8 percent plan to write in a candidate, and 17 percent haven't decided who they'll vote for—or if they'll even vote for president.

Meanwhile, the DHM survey shows Gov. Kate Brown cruising to reelection, leading Republican challenger Bud Pierce 43 percent to 35 percent.

The survey was conducted Sept. 1-6 of 517 registered Oregon voters.

There's good reason to doubt DHM's numbers. In May, the polling firm released a survey showing Clinton leading U.S. Sen. Bernie Sanders (D-Vt.) 48 percent to 33 percent. She lost that primary by 10 points—a 15-point swing, and a huge embarrassment for DHM Research.

Correction: This post incorrectly described Libertarian Party candidate Gary Johnson as the Independent Party candidate. WW regrets the error.