It isn’t likely to happen because one of the steps involved includes getting approval from the Oregon state legislature which is firmly Democrat and unlikely to let these counties go. But they put their vote where their mouths are, and they want out:
Voters in five rural Oregon counties approved measures on Tuesday to consider joining the state of Idaho, a part of a long-shot grassroots movement to break with a state dominated by liberal voters west of the Cascade Mountains.
Voters in Malheur, Sherman, Grant, Baker and Lake counties all approved measures that would require county officials to take steps to promote moving the Idaho border west to incorporate their populations.
…
“This election proves that rural Oregon wants out of Oregon. If Oregon really believes in liberal values such as self-determination, the Legislature won’t hold our counties captive against our will,” said Mike McCarter, a conservative activist who heads the group. “If we’re allowed to vote for which government officials we want, we should be allowed to vote for which government we want as well.”
The Hill, “Oregon counties vote to secede to Idaho,” 5/19/21
The governor of Idaho is onboard with the idea, but again there is at least one other step that is unlikely to get the needed approval to change the state lines. Aside from the Washington state legislature giving approval, also needed is ratification of the change from the U.S. Congress which is also controlled by the Democrat party. That ain’t gonna happen.
So it’s a nice try, but it’s going nowhere.