Outgoing Liberal leader Troy Buswell says his embarrassing and infamous indiscretions played a part in his decision to step down.
The Western Australian Opposition Leader has been at the centre of controversy ever since he admitted sniffing the chair of a female Liberal Party colleague in 2005.
Other drunken incidents have made him virtually unelectable and Mr Buswell said his decision was carefully measured out to better his party.
"I didn't just get up and decide to throw all of that opportunity and that responsibility away on a whim," he said.
"I did it after a very sound thought process, guided by the simple application of a principle.
"And that principle is: I will do what is in the best interest of the Liberal party."
Mr Buswell said he wants the focus to be on the failures of the Carpenter government and not him.
"I do not want to give the government the opportunity to take the focus off of its failings by engaging in cheap personality based politics," Mr Buswell told a media conference in Perth.
"I give an assurance today that whoever replaces me as leader of the parliamentary Liberal party will have my 100 per cent support both on the record and off the record."
Mr Buswell said he wanted to play a major role in helping the Opposition defeat the government at the next election, and did not intend to leave parliament.
The next poll is due before May 2 next year, but anticipation is mounting that Premier Alan Carpenter will call an election within months.