Martin Sime, chief executive of the Scottish Council for Voluntary Organisations (SCVO), has already been accused of being too close to the SNP, and of trying to engineer support for a second question on Alex Salmond's behalf.
More powers, or Devo Max, would be a fallback for the SNP if voters say No in 2014, but the lack of a credible outside advocate makes it hard for Mr Salmond to justify it on the ballot.
Now a draft position paper written by Mr Sime, and obtained by The Herald, shows he wanted the SCVO to lobby for a second "home rule option".
His efforts were in spite of SCVO convener Dr Alison Elliot insisting in January that the organisation was "not launching a campaign to get a second question on the ballot paper".
Mr Sime was ultimately rebuffed by the SCVO policy committee, who were unhappy the organisation's 1300 members had not been consulted, and who wanted the SCVO to take a more moderate stance.
Mr Sime's paper went to the committee in April, when the SCVO was considering its response to the SNP Government consultation on the referendum.
He said a key message should be "SCVO believes it is desirable to have a home rule option, short of full independence, included in the referendum", and gave six reasons, including public desire for it and voters feeling disenfranchised by a Yes/No vote.
He dismissed "political opposition" to a second question as "entirely tactical" and said opponents had "failed to provide a narrative for the development of devolution" after 2014.
Mr Sime said the SCVO should say "a second question can be both fair and decisive".
After negative feedback, the consultation response was watered down, and merely said the SCVO believed "all options should be on the table".
Willie Rennie, leader of the Scottish LibDems, who last week called for Mr Sime to quit for being in email contact with one of the First Minister's special advisers about a second question, said he had "nailed his colours to the mast".
He said: "Martin Sime sides with the SNP by openly criticising opposition parties and accusing them of failing to develop new policy on devolution.
"He impugns our motives for opposing a second question.
"The concerns I and others have about Martin Sime's lack of impartiality have been deepened by this paper."
A spokeswoman for the SCVO said the paper had been "designed to support thorough discussion".