Suppose they gave a crisis and nobody came? Suppose Sinn Fein and the DUP told us to tremble because Stormont would collapse in the morning over the other side's attitude to policing, and everybody said, “Away o' that,” and went on about their business?

Could it happen? Will Sinn Fein walk out if the DUP doesn't agree a fixed early date for devolution of policing?

It cannot be the effect of devolution on the practicalities of policing which has agitated Sinn Fein.

I haven't heard a single Sinn Fein community worker say, re joyriding, drugs, anti-social behaviour and the like, that what's needed here is devolution of policing powers.

It's hard to see what day-to-day difference devolution would make. Ministers, whether direct rule or devolved, don't dictate operational procedures. The speed of response to distress calls, for example, will reflect priorities and levels of staffing: nothing to do with the chain of accountability. The crack of a baton on the skull or the chest-spasm from a taser won't feel different for being administered by an officer mandated under devolution rather than direct rule.

It's doubtful whether the man or woman on the Shantallow bus will notice when/if policing is devolved if it isn't reported in the papers. So, what's the big deal? Why did the SF press office distribute the text of a speech by Caoimhghín Ó Caoláin the weekend before last, declaring that the party would pull out of the Executive if the DUP didn't move sharpish towards devolution of policing? Why, after Peter Robinson emerged from purdah to accuse Sinn Fein of play-acting, was Alex Maskey sent out to pull back from Ó Caoláin's position?

Sinn Fein had not threatened to pull out of the Executive, insisted Maskey. But Ó Caoláin had: “If we are forced to conclude that change will not be forthcoming from the Executive, then we will have no option but to pull out our Ministers and seek to put pressure where responsibility ultimately lies, which is on the British Government in London.”

The uncharacteristic uncertainty of Sinn Fein's performance made it no easier to determine whether the crisis was real and, if it was, whence it had arisen.

The reason it's hard to determine how real the crisis is, is that it's not about the normal stuff of political exchange or reportage, not about personalities or practicalities, but about ideology. In the end, all policing is political. The fundamental role of every police force is to defend the State in whose name it operates and whose authority it symbolises and enforces. From time to time, all police forces defend the State against discontented citizens.

Even in calm times, the police force is the State institution with which citizens are most likely to have politically abrasive contact. You might deal with the tax authorities or the health or planning services on a regular basis for years and get no inkling of the nature of the State. But a single contact with the cops can clue you up in an instant about the sort of State you are living in.

It's when you accept the police force that you've accepted the State. Herein lies the reason the Sinn Fein ardfheis which last year gave the go-ahead for acceptance of the PSNI added a condition: that control of policing be transferred from Westminster to Stormont — from British to Irish politicians, the Irish politicians including as a crucial element representatives of nationalism in the shape of Sinn Fein.

To back the police without securing a share in control for nationalists would be to accept the authority of a State defined by Britishness, not a State which could be represented as being in transition from Britishness to Irishness.

This is what makes devolution of policing a more critical issue for Sinn Fein than for any other party. Which raises another question: why didn't SF negotiators at St Andrews insist on the issue being tied down? Given its enormous importance for the party, why didn't they insist on last May as a deadline rather than a target? Why didn't they get it in writing?

The statement by the two governments which the party is now relying on — “It is our view that the implementation of the (St Andrews) agreement published today should be sufficient to build the community confidence necessary for the Assembly to request the devolution of criminal justice and policing from the British Government by May 2008” — falls a semantic mile short of a deadline.

One school of thought has it that the SF negotiators just had an off day at St Andrews.

This hardly seems likely.

But what, then?

Could it be that they misread their own rank-and-file's adherence to the ideology they'd fought the war on?