Justin Napoleon Mammarella was set to become the next member for Melton, but then he lied to Victoria's corruption watchdog about the purpose of 713 taxpayer-funded envelopes.
The 46-year-old pleaded guilty in the County Court on Monday to conspiring to attempt to pervert the course of justice, perjury and possessing an imitation firearm without the proper permit.
The Independent Broad-based Anti-corruption Commission started investigating the Cairnlea office of former upper house Labor MP Khalil Eideh when it became the centre of a branch stacking scandal to help Mammarella's political aspirations in 2017.
Between January and March 2018, Mammarella conspired with his father Umberto 'Robert' Mammarella, Angela Scarpaci and Jeffrey O'Donnell, who worked as electorate officers for Mr Eideh, to tell IBAC the 713 stamped and addressed envelopes were for disability services provider Autism Plus.
They were, in fact, to be sent to voting Labor members in the Melton electorate endorsing Mammarella's tilt for the legislative assembly seat.
The former Melton mayor also admitted on Monday to telling people other than his wife, employer and lawyer that he was to be a witness examined by IBAC.
Mammarella's barrister Christopher Terry told the court the investigation came at a time when Umberto Mammarella was suffering cancer and his condition was worsening.
"Justin Mammarella was effectively placed in an unenviable situation of having to, on the one hand, speak honestly to IBAC and give honest evidence that would likely implicate his father or on the other hand deny knowledge of the envelopes," Mr Terry said.
It was not an excuse for the actions, but puts them in context, he said.
Mr Terry also explained that the imitation antique firearm found at Mammarella's home when IBAC searched the property was a forgotten collector's item that had fallen foul of changed laws.
When the fake gun was originally bought, it did not need a permit, the court was told.
Mammarella suffers PTSD from an experience that predates the offending and has some physical ailments, but would be able to do community work, Judge Rosemary Carlin was informed.
He will be sentenced by Judge Carlin at the County Court on Thursday.
