Oregon Gov. John Kitzhaber resigned effective Wednesday, Feb. 18, in a letter submitted to Secretary of State Kate Brown.

"I am announcing today that I will resign as Governor of the State of Oregon," he wrote in a statement released just after noon Friday.

Brown, also a Democrat, will be sworn in as Oregon's 37th governor, but the timing of that ceremony is uncertain.

In just four months, a public corruption scandal involving Kitzhaber and his fiancee, Cylvia Hayes, has hobbled one of Oregon's most durable politicians. Kitzhaber, a public official for 37 years, was sworn in for a historic fourth term as governor just a month ago. Facing not only a state criminal investigation and an ethics review, Kitzhaber watched his support from fellow veteran lawmakers crumble this week.

The governor's resignation does not end either the criminal investigation or ethics review.

Kitzhaber, 67, did not appear in public on Friday and neither did his fiancee, Cylvia Hayes. Instead, he issued a page-long statement that was released Friday that made clear his pain and frustration with having to abandon what was to be a historic fourth term. Yet, he wrote, he understood why the move was necessary.

Criticism had mounted in recent weeks over how Kitzhaber had handed Hayes' roles as an unpaid clean energy and economic policy adviser in his office, and as a consultant paid to promote the same topics. Since Kitzhaber took office in 2011, Hayes had collected at least $213,000 from contracts, records showed.

Questions remain as to whether Hayes reported some of that income on her federal taxes.

Last week -- the day after Rosenblum called the allegations "serious" and "troubling" -- newly released emails showed Hayes directing senior officials as Kitzhaber lent support to hiring a key expert on a policy Hayes pushed.

"I understand that I have become a liability to the very institutions and policies to which I have dedicated my career and, indeed, my entire adult life," he wrote. "As a former presiding officer I fully understand the reasons for which I have been asked to resign."

Kitzhaber had met with his staff midmorning to tell them his plan to step down.

"It is not in my nature to walk away from a job I have undertaken -- it is to stand and fight for the cause," he wrote in his statement. "For that reason I apologize to all those people who gave of their faith, time, energy and resources to elect me to a fourth term last year and who have supported me over the past three decades. I promise you that I will continue to pursue our shared goals and our common cause in another venue."

The governor continued, "I must also say that it is deeply troubling to me to realize that we have come to a place in the history of this great state of ours where a person can be charged, tried, convicted and sentenced by the media with no due process and no independent verification of the allegations involved. But even more troubling -- and on a very personal level as someone who has given 35 years of public service to Oregon -- is that so many of my former allies in common cause have been willing to simply accept this judgment at its face value."

Reporters had crowded the lobby of the Governor's office at noon, expecting that Kitzhaber or one of his staff would appear to make a statement in person.

But copies of his resignation letter began circulating on Twitter, and the announcement came quietly via email just before 12:15. Reporters stayed in the lobby for the next hour, then slowly began to trickle out as it became clear neither Kitzhaber nor his communications staff would appear in person.

State officials, organizations and unions issued statements Friday commending Kitzhaber's work over his past three terms as governor and showing support for Brown.

"It is my hope that we view his legacy not just through the narrow prism of these recent months, but the full scope of his decades of service," said Labor Commissioner Brad Avakian in an emailed statement. "As Secretary of State Kate Brown takes the helm of Oregon government, I know that her colleagues and I stand with her as we embark on a new chapter for our state."

House Speaker Tina Kotek and Senate President Peter Courtney had met with Kitzhaber Thursday morning and urged him to resign.

In a statement issued not long after the resignation announcement, Courtney highlighted Kitzhaber's lengthy tenure as Oregon's governor.

"He was elected and has served as Oregon's governor for more than 12 years - longer than anyone else," he wrote in a statement. "No public servant has given more to Oregon... I know that together Oregon and her people will get through this."

Kotek didn't comment immediately, but issued a statement Friday afternoon saying she supported Kitzhaber's decision.

"In 2011, I worked closely with the governor during his signature effort to transform how health care is delivered to low-income Oregonians under the Oregon Health Plan," she wrote. "That work fundamentally changed health care in Oregon, and will benefit families throughout our state for years to come."

One of Kitzhaber's attorneys, Jim McDermott, also issued a statement, making the point -- as had the governor -- that Kitzhaber had been unfairly judged in the court of public opinion.

"I am deeply disturbed by those who believe in due process for violent criminals yet abandon that bedrock principle in the case of a duly-elected governor," he wrote. "He served our State with distinction. His career didn't deserve to come to this premature end.

Senate Minority Leader Ted Ferrioli, R-John Day, outlined his agenda while speaking to a gathering of the Oregon Wheat Growers League.

"What should be a day of celebration (for Oregon) is turning into a day of reflection and mourning," Ferrioli told the crowd gathered in the Capitol. "We appear to be nearing the resignation of our governor and the investiture of a new governor."

He said he had been asked to attend Brown's swearing-in as a sign of solidarity but would not.

Instead, Ferrioli said, he planned to return home "to grieve for the departure in disgrace of one governor and to hope for the healing that can only come if the next

governor turns away from policies that put symbolic

gestures ahead of the real needs of our citizens."

We'll continue updating this story. Find more news on Kitzhaber's resignation at OregonLive.com.

Ian Kullgren and Rob Davis contributed to this report

-- Laura Gunderson

lgunderson@oregonian.com

503-221-8378 @lgunderson