The warning seems to be directed at David Bertschi and George Takach, who owed $155,025 and $136,000 as of last November's reports to Elections Canada.
"The suggestion has been made that one or more candidates may have failed to adhere to the maximum debt rule that was included in the leadership financial rules adopted by the party," Jack Siegel, chair of the "national green light committee," said in a letter to former leadership contenders.
Taking on more than $100,000 in leadership race debt "may therefore be a relevant factor in considering the green-lighting of a candidate, if his or her campaign did in fact exceed the debt limit," Siegel wrote in the letter, which the party provided to CBC News.
Bertschi ran for the Liberals in Ottawa-Orleans in 2011 and wants the nomination for the 2015 election. That's the same riding in which Andrew Leslie, the former head of the Canadian army, plans to run for the nomination.
Barring Bertschi, who already has an established organization in the riding, for going over the debt limit would clear the path for Leslie, who was featured at the party's convention last month as a keynote speaker, and has been named as an adviser to Liberal Leader Justin Trudeau.
The party has promised open nominations, but, as Siegel points out in the letter, party leaders have to endorse a nominee for a person to be acknowledged as the party's candidate.
"The prospect of an individual with the profile of a previous leadership contestant being nominated as a candidate of the Liberal Party, and then having that nomination revoked is something that would be most embarrassing and troubling to candidate and party alike," Siegel wrote in the letter.
Must repay leadership debt
The party is also warning former leadership contenders that they must be on the way to repaying their leadership debt.
Siegel said "measures for complete debt repayment" will be part of the process used to decide whether nominees get the party's endorsement.
"In order for your candidacy to be approved by the national green light committee, it will therefore be necessary for you to provide a written report of all of your debt retirement progress to date, as well as a concrete and detailed plan for your continued debt retirement. This is an absolute requirement to the approval of your candidacy," Siegel wrote.
Even current MPs won't be endorsed if they have leadership debt unless they've submitted to the party "a reasonable and practical debt retirement plan." That endorsement will be revoked "if past and ongoing progress and compliance with that plan is not demonstrated," Siegel said.
Marc Garneau, Joyce Murray and Justin Trudeau, who won the race to become federal Liberal leader, already sit in the party's caucus.
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