Liberal MPs will confront a stark choice next week between propping up a deeply wounded prime minister or trying a fresh start. They know each course is fraught with big risks.

With the crucial vote not until Tuesday, anything can happen in this extraordinary volatile situation.

Backbenchers will be under huge pressure from the Prime Minister’s Office (PMO) and close supporters. But Team Abbott will need the kid gloves on, or they will reinforce the criticisms about the “command and control” style.

On the other hand, the MPs will also be acutely aware of the evidence pointing to the dangers of retaining Tony Abbott. This includes the feedback they’re getting from their electorates, and the polling, of which there will be more between now and Tuesday, including the influential Newspoll.

A Seven News ReachTEL poll done on Thursday night had the government trailing 45-55%. When people were asked how they’d vote if Malcolm Turnbull were leader there was a massive turnaround – the Coalition led 54-46%. A hypothetical Julie Bishop leadership had the Coalition ahead 51-49%.

Asked to choose between Turnbull and Bishop to lead, Turnbull polled 56.5% to Bishop’s 43.5% – although Bishop was decisively ahead among Coalition voters and Turnbull was strongly in front among Labor voters.

Ministers – including Mathias Cormann, Peter Dutton, Jamie Briggs, Bruce Billson, Josh Frydenberg and Kevin Andrews – rushed out late on Friday to oppose the spill motion from Luke Simpkins and Don Randall, which is to open both Abbott’s position and that of deputy Julie Bishop.

Bishop and Turnbull are under intense attention from media and colleagues. Abbott, in his brief take-no-questions appearance which lasted less than two minutes, said he’d spoken to Bishop and they’d “stand together” against the spill.

But Bishop made it clear that while she is opposing the spill, if it passed all bets would be off, saying in a statement that: “I agreed with the Prime Minister that due to cabinet solidarity and my position as deputy there should be support for current leadership in the spill motion”.

Turnbull was conspicuously missing in the ministerial dash to shore up Abbott.

One factor that could affect the numbers is whether it is a secret ballot or a show of hands. Chief Government Whip Philip Ruddock indicated this was up to the leader.

An open ballot would test the courage of those critical of Abbott but ambitious for their own future. Some might fear the wrath of the PMO if the motion failed but they had voted for it. Ministers could not break ranks if the vote were public – for a few, it might be a different story if it were a secret vote.

But an open ballot would bring resentment among the troops and reduce the credibility of a win. Cormann predicted it would be a secret ballot.

If Abbott fends off the motion the size of the margin is important. A sizeable “yes” minority would just encourage another attack later in a classic two-stage operation.

If there’s not a declared alternative, that probably helps Abbott. In the next few days, MPs will want to try to suss out what Turnbull and Bishop would do if the spill were carried. But the pair will have to take into account what their situations would be if they’d privately indicated they were willing to be candidates but then the spill vote was lost.

And then there is the question of what Abbott would do if the vote were carried – would he enter and complicate a subsequent contest?

This campaign against Abbott has been a bottom-up one by backbenchers increasingly afraid he will cost the Coalition government and them their seats. It’s quite broadly based across the country, with a significant number of people networking in the run up to Friday’s formal move. “It looks orchestrated,” observed cabinet minister Andrew Robb. The grassroots nature of the backbench revolt makes it hard for ministers to judge the numbers.

A perfect storm of events came together for the dissidents. The backflip on a backflip over the Medicare changes symbolised a flaky approach to policy; Prince Philip’s knighthood pointed to Abbott’s eccentricities; the Queensland rout highlighted that the voters are brutal to governments they come to dislike and distrust – and they make up their minds quickly.

Abbott is making a central point of his appeal for support that the spill sponsors “are asking the party room to vote out the people that the electorate voted in”.

“We are not the Labor party and we are not going to repeat the chaos and the instability of the Labor years,” he said in Friday’s statement.

It’s a pretty good imitation, however.