By Mark Mardell BBC chief political correspondent

The political operation on Monday will boil down to making "No, not yet" sound as much like "Yes, in a while".

The central litmus test, at least for the pro-euro lobby, is whether or not a referendum is ruled out before the next election.

To any objective observer this matters as little as which end you should open an egg but this, you'll remember, was the cause of war in Gulliver's Travels.

And it will lead to skirmishes and political bloodshed if not actually to open warfare.

It's beyond doubt that the opposition will portray Monday's outcome as the result of a power struggle between chancellor and prime minister, with one of the key players emerging as a diminished loser.

Depressingly for the high minded but na�ve folk who argue for politics free of personality, that's exactly how most government insiders see it as well.

Overcoming obstacles

The "before or after the election" argument is about whether the cabinet is going to show enthusiasm for an early referendum, eagerly dismantling the roadblocks to entry that the chancellor has helpfully pointed out in his stacks of documents.

Tony Blair, the natural optimist, has always been enthralled by his own powers of persuasion

Or whether ministers will stand before the obstacles, rubbing their collective chins and vaguely hoping that in time the economic and social weather will erode them and allow passage.

According to one senior politician, it is all a question of character.

Tony Blair, the natural optimist, has always been enthralled by his own powers of persuasion.

He's now buoyed up by the extraordinary experience of leading a country into a war it overwhelmingly didn't want and successfully persuading them that with hindsight they did want it after all.

Given that it's a brave advisor who says: "But, prime minister, half the country thinks you're a liar", he still believes he can, at some undetermined date in the future, win a euro referendum.

Blair's tightrope

At a certain stage in most prime ministerial careers the leader seems to regard a certain degree of recklessness as obligatory.

Rather like a high wire artist showing off increasingly dangerous tricks that only he can manage, leaders think it demonstrates the particular quality that only they can bring to the party.

Of course for Blair to lose a referendum would be pretty bad. Resignation would be a distinct possibility.

But what the heck, he'd have gone out on a moral high and there's nowhere else to go.

Fudging it

It's rather different for the chancellor.

Gordon is by nature gloomy. He doesn't think the opinion polls can be shifted by the sturm and drang of charismatic leadership but by the slow build up of overwhelming certainty.

If the country failed to take the chancellor's advice on a central economic matter, resignation would seem inevitable.

An inglorious end to a career that, he at least believes, could last much longer and go much further.

The end result of this will doubtless be a fudge: the political trick is to make compromise seem statesman-like and dither look like determination.