By Martina Purdy
BBC NI political correspondent
The assembly is due to jointly nominate Martin McGuinness and Peter Robinson but will it happen?
An Irish government official once described Sinn Fein as "institutionalised negotiators."
The party, he had concluded, simply could not resist a negotiation, and didn't seem to know when to stop.
The description springs to mind as Stormont is gripped with fevered speculation that Sinn Fein is once again in negotiating mode.
It's no secret the party is frustrated that the DUP is using its veto to block a range of issues, not least the devolution of policing and justice.
After all Sinn Fein had anticipated this would have happened last month.
Instead, the DUP is insisting that it will not be hostage to fortune by giving a date and is insisting there is not sufficient confidence in the unionist community.
The PUP leader, Dawn Purvis, however, has countered that the crisis of confidence is within the DUP, not the unionist community.
Whatever the truth, Sinn Fein wants the issue resolved, as the party has its own supporters to placate and cannot afford to look weak in the face of a DUP veto.
It also wants to safeguard the future of the Maze site, its education reform proposals and the future of the Irish language.
At St Andrews the government promised an Irish language act, which the DUP promptly scrapped.
Nominations for first and deputy first minister due on Thursday
If Sinn Fein refused to nominate its candidate, Peter Robinson would not be able to become first minister
The two parties would then have seven days to resolve the issue
If still deadlocked, the secretary of state would have to call an election
While this may keep the DUP base happy, it is having the opposite effect on Sinn Fein's grassroots.
So, that brings us to Thursday when Ian Paisley is due to retire as first minister and the assembly is due to jointly nominate Peter Robinson and Martin McGuinness as the new first and deputy first minister.
That may well happen. But not everyone is convinced.
Indeed, a DUP source has claimed one senior republican is not even attempting to hide the fact that the party is considering its position and may exercise its own veto.
Other DUP sources are shrugging off the speculation but they must be a little worried that Martin McGuinness's party isn't bluffing.
If Sinn Fein refused to nominate, Peter Robinson would not be able to become first minister this week.
Instead, the two parties would have seven days to resolve the issue and if they remained deadlocked the secretary of state would have to step in and call an election to break the deadlock.
However, the Ulster Unionist MLA Danny Kennedy suggested on the BBC's Stormont Live programme the poll could be delayed until the autumn rather than having one in the middle of the marching season.
Whispers that Sinn Fein may not nominate surfaced last week - from both Sinn Fein and DUP sources.
Officially however, Sinn Fein is refusing to be drawn.
Why is this speculation not being killed off?
In fact, it's been fuelled by a statement issued by Gerry Adams.
The Sinn Fein president said it was his party's intentions to build upon the progress made in bedding down the institutions.
He adds: "We continue to be involved in detailed discussions aimed at achieving this. That is our focus at this time."
That sounds a bit like a negotiation.
Of course it suits Sinn Fein for the speculation to continue.
It's playing a game of poker and the media are clearly being used to get the message out that the DUP cannot take their cooperation for granted.
But is it all just bluff? Or is Sinn Fein serious about an election.
Sinn Fein is a party of experienced negotiators who know full well that there is no point in upping the ante if you can't follow through when your opponent calls your "bluff."
It's likely Sinn Fein has been examining its options for some time.
An election certainly does not suit the DUP just now, particularly in light of the Dromore by-election when it lost a chunk of its base to the Traditional Unionist Voice, enabling the Ulster Unionist Party to win the seat.
If the Dromore by-election result was replicated across Northern Ireland, one thing is certain: the DUP would not be sitting on 36 seats.
The fact is the DUP is a little too powerful for Sinn Fein's tastes right now.
Might Sinn Fein see some advantage in the Traditional Unionist Voice splitting unionism?
Might it get its feet under the table of the first minister's office if the unionist vote splits and the SDLP falls further behind?
Does Sinn Fein see the Traditional Unionist Voice as being at its most potent now - or in three years time?
Could Jim Allister's Traditional Unionist Voice replicate its Dromore by-election success?
An early election may suit Sinn Fein.
Does Sinn Fein for example want to be going to the polls in 2011 with the SDLP shouting about what it has called "the (Conor) Murphy tax" - that is household water bills?
Does it want to be going to the polls to be judged on education reform's outcome which could include compromise?
Or would it rather go to the polls now staunchly defending its plan to phase out selection?
Does Sinn Fein want to wait for Fianna Fail's army to come marching onto its patch - with or without the SDLP's help?
Might it be better to go to the polls now before either the SDLP regroup or Fianna Fail invades?
Does Sinn Fein want to to go the polls in three years with the DUP having vetoed some key demands?
Or does it want to go to the polls now beating its chest and promising to give Peter Robinson and the DUP the "proverbial bloody nose"?
Of course there are risks involved in playing this game.
George W Bush might cancel his trip to Stormont.
That is more likely to annoy the DUP than the republicans. In fact their grassroots will probably cheer.
Sinn Fein has conceded some of its holy grails to achieve power-sharing and north-south cooperation.
And forcing a crisis could put this in danger and delay power-sharing for years to come with the prospect of a dangerous vacuum opening up.
On the other hand, it reopens negotiations. Does Sinn Fein think it can do better? Is it addicted to negotiating?
Whatever the truth, the question for Sinn Fein is - does it have more to gain or more to lose?
If nothing else, this question must surely be concentrating minds in the DUP leadership.
And even if it is all a bluff and Sinn Fein ends up nominating, it may have taught the DUP a valuable lesson: there are consequences for saying No.