AN ALASKA ethics inquiry has found that Sarah Palin, the US Republican vice-presidential candidate, abused the power of her office by pressuring subordinates to fire a state trooper involved in a feud with her family, a report has said.

The finding, published last Friday, cast a cloud over John McCain's controversial choice of running mate for the November 4 election. On the day it was published McCain reined in an aggressive strategy against Barack Obama that had failed to cut into his Democratic rival's lead.

After a week in which he and Palin fiercely attacked Obama and urged supporters to question his fitness to be president, McCain switched to a milder tone, calling on frustrated loyalists to respect the Illinois senator.

Supporters appeared surprised by his conciliatory approach, booing at a Minneapolis rally when he told a sceptical backer that Obama was a "decent person and a person that you do not have to be scared of as president of the United States".

The Alaska inquiry centred on whether Palin's dismissal of the state's public safety commissioner, Walt Monegan, was linked to her personal feud with a state trooper, Michael Wooten, who was involved in a contentious divorce with the governor's sister.

The inquiry found that while it was within the governor's authority to dismiss Monegan, Palin violated the public trust by pressuring those who worked for her in a way that advanced her personal wishes.

"Governor Palin knowingly permitted a situation to continue where impermissible pressure was placed on several subordinates in order to advance a personal agenda, to wit: to get Trooper Michael Wooten fired," the report said.

The investigation was commissioned in July by Alaska's legislative council, composed of 10 Republican lawmakers and four Democrats.

Responding to the probe's findings, the McCain-Palin campaign said: "The report shows that the governor acted within her proper and lawful authority in the reassignment of Walt Monegan."

The campaign has attacked the investigation as a partisan effort led by supporters Obama and said the public safety commissioner was dismissed because of poor performance.

"Lacking evidence to support the original Monegan allegation, the legislative council seriously overreached, making a tortured argument to find fault without basis in law or fact," the campaign said in a statement.

The McCain-Palin campaign has said that the Palins were justified in their actions because they were trying to protect their family from Wooten, who they claim had made threats of violence.

According to the report, Palin allowed her husband, Todd Palin, to use the governor's office and resources to continue to meet and speak to state employees in an effort to find some way to get Wooten fired.

"The problem with power is that people pay attention to it, and it's very easy to ... use it in the wrong way. And you have to leave personal business at home," said Alaska senate president Lyda Green, a Republican member of the legislative council.

The report did not recommend any action be taken against the governor, but called for changes in statutes for handling government personnel.

While the "Troopergate" scandal has garnered national media attention, the Obama campaign has not used the inquiry to attack McCain or Palin.

The report said the governor's public statements about fearing that Wooten would attack her family were not true.