Church observers said the step would be a serious setback, but not a fatal one, to the National Review Board that Keating chairs.
Spokesman Dan Mahoney said Keating would send a resignation letter to Bishop Wilton Gregory, president of the U.S. Catholic hierarchy, and issue the text Monday or Tuesday. The Los Angeles Times first reported on Keating's plan Sunday.
Mahoney said Keating and Gregory spoke Saturday and that Gregory did not ask Keating to leave but indicated "whatever you decide, I'll respect."
Mahoney said Keating is still undecided on when his resignation will take effect. The board's next meeting is July 28-29 in Chicago.
Public criticism by Los Angeles Cardinal Roger Mahony and fellow members of the National Review Board of remarks Keating made "hastened his decision," Keating's spokesman said, but "he has been talking for several months about leaving."
The resignation follows a Times interview where Keating said of unnamed church officials: "To act like La Cosa Nostra and hide and suppress, I think, is very unhealthy. Eventually it will all come out."
Mahony, whom Keating accused of listening "too much to his lawyer and not enough to his heart" in dealing with the panel's investigation, called Keating's comments "the last straw."
The cardinal said he would ask other bishops to consider calling for Keating to step down during the full hierarchy's meeting that opens Thursday in St. Louis.
The Rev. Thomas Reese of America magazine, a New York-based Jesuit weekly, said Keating's departure is "a setback for the bishops" and "another stumble on the way to cleaning up the bishops' reputation."
"The governor was obviously giving some of the bishops ulcers in the short run, but in the long run, if he had stayed around, any report he issued would have absolute credibility," he said.
Keating's resignation "basically sends the message that if you're too much of a straight shooter you're going to get pressure to resign," said Deal Hudson, editor of Crisis, a conservative Catholic magazine in Washington, D.C.
Hudson said that he spoke with Keating on Friday about the faceoff with Cardinal Mahony and that the former governor gave no hint he would consider resigning.
Representatives of abuse victims expressed dismay.
"It's very disturbing that a couple of candid remarks are apparently so upsetting to the bishops," said David Clohessy, national director of Survivors Network of those Abused by Priests, which also meets in St. Louis this week. "Here's a devout, conscientious Catholic lay person who volunteered his time and essentially his reputation to get the bishops out of trouble and he's suddenly forced out."
Susan Archibald, president of The Linkup, another victims' organization, said "the problem is he's stepping down in reaction to criticism from a bishop, and what he said was the truth. If they hesitate to speak out against bishops, then what good is the process?"
Voice of the Faithful, a 30,000-member lay reform group based in Newton, Mass., regretted Keating's departure and urged all bishops to "cooperate completely and unambiguously with the National Review Board in its search for truth."
Prominent Washington attorney Robert S. Bennett, the review board member who is running its investigation of why the abuse scandal happened, said Keating's resignation would not slow the board's work.
"There are many very strong and outspoken members on this board who are going to remain on the board and who are going to see to it that the bishops honor their commitment to protect children and the promises they made," Bennett said.
Besides Bennett's investigation, the board is sponsoring a survey of the extent and patterns of abuse cases based on reports filed by all 195 U.S. dioceses. The verbal flare-up with Keating stemmed from Cardinal Mahony's initial refusal to participate in that survey unless procedures were changed.
In a Sunday statement the cardinal's office said "nothing should distract us from our most urgent goal: the protection of all our people, especially our children, from the sin and crime of sexual abuse."
Gregory appointed Keating as chairman as well as the review board's other 12 members as part of the reform "charter" the hierarchy approved a year ago.
The charter doesn't specify what to do if the chairman resigns. Reese assumes Gregory would choose the new chairman and someone acceptable to continuing board members, most likely one of those members.
Reese said "the bishops are beginning to realize that being more transparent and open about these issues is more difficult than they anticipated." But he thinks Keating's "intemperate" quotes "got in the way of doing the job the review board is there to do."
By Richard N. Ostling