OTTAWA, Aug 19 (Reuters) - Canadian Prime Minister Stephen Harper struggled to shake off an ethics scandal dogging his re-election campaign on Wednesday as the criminal trial of a former ally threatened to erode voter support and cover-up allegations spread to his chief of staff.
The crisis is one of the most serious to hit Harper's right-of-center Conservatives, who are seeking to extend a near-decade in power in the Oct. 19 election. Amid an uproar over revelations in the trial, involving dubious expenses filed by a Conservative senator, polls show the party is likely to lose its majority in the House of Commons, and might even be defeated.
The trial has heard that Harper's current chief of staff, Ray Novak, knew more than he has admitted about Conservative efforts to cover up improper expense claims filed by Senator Mike Duffy, once seen as valuable Harper ally. In 2013, Harper fired his then chief of staff, Nigel Wright, for his involvement in the scandal.
Opposition parties say Harper is not telling the truth about how much he knew of a plan to pay off Duffy, who faces fraud and bribery charges.
On the campaign trail, reporters repeatedly asked Harper why Novak is still on the job, and opposition leaders called for Novak to be fired. Both sides are watching the clock, wondering whether the furor will last long enough to affect the election, still two months away.
The long-awaited trial, related to a scandal that broke in 2013, is scheduled to adjourn on Aug. 28 and not resume until November, after the election.
Harper, crisscrossing the country, tried to remain focused on his campaign.
"I am not going to discuss individual things before the court," Harper told reporters in London, Ontario, when asked repeatedly why Novak was still in his job.
At one Harper campaign stop this week, a Conservative supporter verbally attacked reporters for focusing on the Duffy trial and had to be removed from an event.
The opposition is keeping the pressure on.
"Canadians are not fools. They know that it's clear Mr Harper has not been telling the truth," Liberal leader Justin Trudeau told reporters in Winnipeg.
Conservatives say privately that Duffy's trial is so complicated it may not resonate with voters. But in a sign of unease among some supporters, former Conservative legislator Randy White told CTV television on Tuesday he might vote for the left-leaning New Democrats, who have a slight lead in most polls.
$1=$1.32 Canadian Reporting by David Ljunggren; Editing by Peter Galloway