The Liberal leader says open nominations mean allowing party members in each riding to choose whom they want to carry the party's banner in the next election.
But he says it doesn't mean letting contenders employ whatever nasty, divisive tactics they choose in order to secure a nomination.
Trudeau's team last week informed Christine Innes, a two-time Liberal candidate and wife of ex-MP Tony Ianno, that she won't be allowed to seek the party's nomination for the coming byelection in Toronto's Trinity-Spadina or in any other riding for the general election in 2015.
Innes was blocked because her campaign team — specifically, Ianno — had allegedly tried to bully and intimidate young volunteers and had been bad mouthing both Trudeau and one of his star recruits, rookie Toronto Centre MP Chrystia Freeland.
Innes has adamantly denied the charge.
She maintains she was punished for refusing to guarantee she wouldn't run against Freeland for the nomination in University-Rosedale, one of three new downtown Toronto ridings created for the next election under redistribution.
In his first comments on the controversy, Trudeau suggested Tuesday that the nomination contest for the Trinity-Spadina byelection will be more open now that Innes is no longer involved.
"There were no other candidates willing to go near Trinity-Spadina given the approach that this particular team did," he said following a speech in Kingston, Ont.
"So, we're glad to see there's actually going to be an open nomination now in Trinity-Spadina."
An audio recording of Trudeau's remarks was made available by his office in Ottawa.
Trudeau denied the move to block Innes was aimed at protecting Freeland or clearing old guard Liberals out of the way for a new team with fresh blood.
Rather, he maintained it was strictly designed to send the message that infighting among Liberals will no longer be tolerated.
"Open nominations, which I continue to be committed to and have always been committed to, is about letting local Liberals choose who is going to be their candidate in the next election," Trudeau said.
"It doesn't mean that anyone can behave in any particular way they like and still expect to become Liberal candidates. ...
"The infighting, the backroom games are not something Canadians want to see and I'm pleased that so far the board and the national executive of the Liberal party have been enforcing rules around that."
Blocking Innes has sparked somewhat of a backlash within the party, with at least one prospective candidate, Zach Paikin, announcing he'll no longer pursue what was likely a long-shot bid for a Liberal nomination in Hamilton.
Other Liberals have criticized Trudeau's team for blocking a female contender because of the alleged actions of her husband. But Trudeau was unapologetic on that score.
"Certainly, the way a campaign team behaves reflects directly on a candidate," he said.
Anyone who wants to run for a nomination must first win approval from the party's so-called green light committee. The committee has spelled out some of the conditions for winning approval, including warning several former leadership contenders that they could be blocked if they don't have credible plans for paying off lingering leadership debts.
Prior to blocking Innes, it had not been clear that overly aggressive campaign tactics were grounds for rejection. Ontario campaign co-chair David MacNaughton has said it ought to have been understood by all Liberals that the leader would not tolerate the kind of infighting that almost destroyed the once-mighty party.
Trudeau said the party will further clarify the rules for becoming a nomination contender "in the coming days."
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