Green MSP Maggie Chapman has refused to confirm whether she intends to support the power-sharing deal with the SNP – or try to bring it down.
Party members are being given a vote on the arrangement as part of the backlash at last week’s major climate target U-turn.
It is also been turned into a vote of confidence in party co-leader Patrick Harvie, who is a minister in the government thanks to the Bute House Agreement between the two groups at Holyrood.
But while Ms Chapman has decided how she’ll vote, the North East Scotland MSP and former Aberdeen university rector refused to reveal her decision.
“I have made up my mind about the Bute House Agreement but I am not going to make this public at this stage,” she said.
“There are conversations with party members in the North East and beyond that I want to have first, and, of course, ongoing discussions with colleagues in parliament.
“I intend to honour my commitments to these groups before going public with any further comments.”
In an email, Ms Chapman explained she would eventually set out her views and reasoning to constituents.
A former Green co-leader, Ms Chapman is viewed as a more independently-minded Scottish Green representative and remains popular among party members.
A party insider said they think it’s likely Ms Chapman’s decision will be “quite influential”.
Other Green MSPs, including Mid Scotland and Fife representative Mark Ruskell, have already confirmed they support the deal.
What caused the SNP-Green fall out?
The future of the co-operation agreement between the two parties was thrown into doubt after the Scottish Government ditched its flagship climate target to cut emissions by 75% by 2030.
A pause on new prescriptions for puberty blockers at Scotland’s only gender clinic for young people also left Green members reeling.
They were quick to demand a vote following the U-turns, and many inside the party suspect they will vote to end the deal despite co-leaders Patrick Harvie and Lorna Slater calling for it to stay in place.
Mr Harvie, who said he recognised the “strength of feeling” among rank-and-file members, has confirmed he’ll quit if his party votes against him.
First agreed by Nicola Sturgeon after the last Holyrood election, the deal sets out an number of areas where the two party’s are aligned.
In return for two junior ministerial posts, it guarantees Scottish Green support the SNP government in major votes.
Mr Yousaf has resisted calls from within his party to allow a similar vote, saying he hopes it would continue.
But the agreement has a number of vocal critics inside the SNP, including Skye, Lochaber and Badenoch MSP Kate Forbes, and Inverness and Nairn MSP Fergus Ewing.
SNP MP Joanna Cherry called for a similar vote among nationalists, saying: “If we are to recover as a party from current challenges we need to address problems like this alliance with a deeply unpopular party on the doorsteps rather than sweeping them under the carpet.”
Asked about the first minister’s refusal to give SNP members a vote, Scottish Conservative leader Douglas Ross said Mr Yousaf was becoming “weaker by the day”.
The Moray MP said: “Most of us can see how damaging the nationalist coalition has been, and now we are seeing senior SNP representatives calling out the failures of the government by having the Greens in government.
“Some of the worst policy failures, such as the deposit return scheme, can be traced back to Green ministers.
“Ultimately, if the Bute House Agreement falls it should be because the first minister has strength to remove the Greens but it looks like the Greens will walk away.
“That just sums up how weak Humza Yousaf’s leadership has been.”
Conversation