OTTAWA - It helped to turn the electoral tide, gave Stephen Harper's Conservatives a boost on their way to power, and sparked heated accusations that the national police were meddling in federal politics.

Now the chief watchdog over the RCMP is set to release a report on whether the Mounties did the right thing by disclosing -- in the middle of the last federal election campaign --- that they were launching a criminal investigation into the actions of the former Liberal government.

Paul Kennedy, head of the Commission for Public Complaints Against the RCMP, announced an investigation of the affair more than a year ago. He's had virtually no public comment since, but will finally deliver his conclusions Monday at an Ottawa news conference.

Ujjal Dosanjh, the Liberal public safety critic, says he's hopeful the report will shed some light on the "strange fashion'' in which the Mounties acted.

Whether they meant to or not, Dosanjh said in an interview Sunday, "the RCMP actually descended into the arena of politics. That kind of serious mistake should never happen.''

Judy Wasylycia-Leis, the New Democrat MP whose letter to former RCMP commissioner Giuliano Zaccardelli prompted the disclosure, doesn't think it's that simple.

"I certainly have no regret about anything I did with respect to this issue,'' she said.

"But this is not an easy, cut-and-dried situation. I think it will be really helpful to have Mr. Kennedy's  recommendations.''

The tangled tale began in the autumn of  2005, before the fall of Paul Martin's government, with an announcement by then-finance  minister Ralph Goodale on Liberal tax policy toward income trusts.

Three was a spike in trading in the popular investment vehicles just before the announcement, leading to speculation that inside information may have leaked to Bay Street.

That in turn led Wasylycia-Leis to write to Zaccardelli asking whether the RCMP would look into the matter. The top cop replied, just after Christmas and with an election campaign in full swing, that the force was not only looking into it but was starting a full-fledged criminal investigation.

A slim Liberal lead in public opinion polls evaporated nearly overnight, and Harper was soon prime minister.

It wasn't until he'd been in office for a year that the force finally laid charges against Serge Nadeau, a Finance Department bureaucrat who was accused of using inside information to personally profit from trades in income trust shares. He has yet to face trial.

It was later reported -- though never officially confirmed -- that charges had been considered against one other person who has never been publicly named. They were abandoned after key provisions of the Security of Information Act -- the federal government's anti-leak legislation -- were struck down as unconstitutional in an unrelated case.

Zaccardelli was adamant throughout the controversy that there was no ulterior motive in the disclosure of the investigation.

"I am not political,'' he declared. "Based on the information I have, I have to make a judgment call . . . I made that decision and I live with that decision.''

Before 2006 was out, Zaccardelli was no longer making the decisions. He was forced from office in the furor over the Maher Arar affair, which saw an innocent man face torture in Syria on the basis of faulty information from the Mounties that erroneously linked him to al Qaeda.

Others who took a hand in defending the force also came to grief -- though in ways nobody could have predicted at the time.

Deputy Commissioner Barbara George, in response to a complaint from the British Columbia Civil Liberties Association, stoutly maintained that the Mounties were only doing their job in the income trust affair.

"The RCMP is a police organization bound by law to investigate criminal activity, whether an election campaign is ongoing or not,'' George wrote in February 2007.

She has since come under fire for her role in alleged mismanagement of the RCMP pension fund and has been accused by a Commons committee of giving misleading testimony and being in contempt of Parliament.

It was left for William Elliott, a career bureaucrat and the first civilian RCMP commissioner in history, to pick up the pieces when he appeared at yet another parliamentary committee in February of this year.

Under questioning about the income trust affair, he admitted the force "does not have adequate policies, guidelines or directions with respect to communications relating to criminal investigations.''

Elliott went on to say the Mounties were "in the process of taking steps to clarify the policies.''

He didn't explain exactly what steps were under way, say when they will be complete or specify what the new guidelines will be.