John McCain's election campaign last night suffered the body blow that Republicans had been bracing themselves for when his vice-presidential candidate, Sarah Palin, was found to have abused her powers in pursuit of a personal feud against her former brother-in-law.
At the conclusion of the ten-week investigation into the so-called Troopergate affair, Palin was found to have breached the ethics rules that govern her conduct as governor of Alaska.
The findings were delivered by an investigator appointed last July by a Republican-controlled committee of the Alaskan state legislature. He began his inquiries shortly before Palin was picked as McCain's running mate, and his conclusions appear certain to lead to questions over McCain's judgment and to allegations that she would be unsuited for national office.
Stephen Branchflower, a former prosecutor, found Palin had breached the Alaska Executive Branch Ethics Act, which states that "each public officer holds office as a public trust and any effort to benefit a personal or financial interest through official action is a violation of that trust".
Branchflower concluded that Palin's feud with her former brother-in-law, Mike Wooten, an officer of the Alaskan state police, was "likely a contributory factor" in her decision to dismiss the head of that force, Walt Monegan. However, he also concluded that this dismissal had been carried out in a "proper and lawful" fashion.
The committee voted to disclose much of Branchflower's report public early this morning after deliberating in secret for more than six hours.
Although eight of the 12 members of the committee are Republicans, they voted unanimously for its publication. Palin has made a number of enemies among her fellow Republicans in Alaska after she picked fights with the party's local leadership en route to election as governor, and then formed alliances with Democrats in a bid to force through her legislative programme.
Palin will probably not face impeachment proceedings, with local Democrats and Republicans saying they have little appetite for such a move. The committee's chairman, Kim Elton, a Democrat, said he agreed with Branchflower's findings but added: "We don't charge people, we don't try people as legislators."
With McCain struggling to overtake Barack Obama in the polls less than four weeks before the election, the report's findings could barely have been worse for the Republicans.
Palin had denied all wrongdoing, and shortly before the report was published her husband, Todd, sought to shoulder some of the blame by admitting he had he repeatedly complained about Wooten, believing him to be a danger to the public.
Wooten had been through an acrimonious divorce and custody battle with Mrs Palin's younger sister, Molly McCann, in 2005. A number of complaints that the Palin family made about him at that time were upheld, and in March 2006 he was disciplined but allowed to keep his job.
Palin came into office as governor of Alaska nine months later, and Monegan came under pressure to fire Wooten immediately after she appointed him the state public safety commissioner.
Monegan told Branchflower he had been summoned to see Todd Palin, who complained that Wooten's punishment had been merely a "slap on the wrist." Monegan said he understood the Palins wanted Wooten fired. "I had this kind of ominous feeling that I may not be long for this job if I didn't somehow respond accordingly," Monegan told the investigator.
Branchflower found that Todd Palin enjoyed extraordinary access to the governor's office and her closest advisers, despite being unelected and having no salaried state post. He used that access to try to get Wooten fired, the report found.
Branchflower criticised Palin for taking no action to rein in her husband, and said there was some evidence that she participated in the effort. "Such impermissible and repeated contacts create conflicts of interests for subordinate employees who must choose to either please a superior or run the risk of facing that superior's displeasure and the possible consequences of that displeasure," the report states.
A further finding of Branchflower's 263-page report was that the office of the Alaska state attorney general, Talis Colberg, failed to comply with his request to release information about the case held in various e-mails.
A number of Alaskan republicans attempted to halt publication of the report with a series of court case, but the state's supreme court dismissed their final bid on Thursday, paving the way for its publication.
Monegan said: I feel vindicated. It sounds like they've validated my belief and opinions. And that tells me I'm not totally out in left field."
McCain's campaign team insisted the Alaskan committee had "overreached" itself. It issued a statement saying: "Today's report shows that the governor acted within her proper and lawful authority in the reassignment of Walt Monegan. The report also illustrates what we've known all along: this was a partisan led inquiry run by Obama supporters and the Palins were completely justified in their concern regarding Trooper Wooten given his violent and rogue behaviour."
The Alaskan state senator Gary Stevens, a Republican, objected to the report while agreeing that its contents should be made public. "I would encourage people to be very cautious, to look at this with a jaundiced eye," he said.