As the Assembly election campaign draws to a close speculation inevitably turns to who will hold what post in the new Northern Ireland government. Any time now speculation will resume too about the next great event in the life of Tony Blair's government - his first reshuffle.

The two events conspire to present something of a dilemma for the Northern Ireland Secretary.

Nobody knows what the Prime Minister has in mind. Labour's rules obliged him to include the members of the elected shadow cabinet in his first administration. A number of them beg to be shuffled off stage.

And at some point Mr Blair will certainly want to recast the cabinet ever more strongly in his own image. But will he want to perform radical surgery next month, or next year - as his government approaches midterm?

Mr Blair's disposition will be a crucial factor in Dr Mowlam's decision. Her instinct, undoubtedly, will be to stay at Stormont during the coming transitional period before the formal transfer of powers to the Assembly.

And senior unionist and nationalist politicians acknowledge the argument in favour of retaining a Secretary of State familiar with the agreement and all its nuances.

The risk for Dr Mowlam is that, if Mr Blair goes for far-reaching change now, she could miss the boat. True, Mr Blair's design could allow for her delayed return to London next February or March.

But, as the wise politician never forgets, events have a terrible way of upsetting the best-laid plans.

Moreover, some putative ministers in the new Northern Ireland executive think there is a strong case for Dr Mowlam's early departure.

On one level, that comes as no surprise. Unionist politicians have little time for her, and nationalists are scarcely more flattering in private. Mr Trimble's antipathy is an open secret; sources say he completed the final week of the multi-party negotiations with barely a word cast in her direction.

Wishing it were otherwise, Dr Mowlam has wearily acknowledged that she has to "leave David to the Prime Minister".

The new arrangements for the government of Northern Ireland suggest tensions aplenty between London and Dublin, as Mr Trimble observed the other day about budgets and the extent to which Westminster can expect to predetermine Northern Ireland policy.

And the relationship between Secretary of State Mowlam and First Minister Trimble could clearly prove explosive.

Pending agreement further down the line, security will remain the chief responsibility of the Secretary of State. But the new order will otherwise see the post drastically reduced. Is it conceivable, asks one source, that Dr Mowlam - having had the pivotal role - would accept "the equivalent of political retirement"?

Soon now, somebody else will be touring America, leading trade and economic missions. There and here, the source ventures, the press will be hanging on the every word of David Trimble, John Hume and their ministers, "leaving the Secretary of State in a backwater, with no profile".

It's hard, somehow, to see that happening to Dr Mowlam. Whatever about the ingratitude of the natives, she is an acclaimed star in Britain - recently (and maybe dangerously, for her) registering a higher popularity rating even than Mr Blair.

But other sources say there is a further objection to her remaining at the Stormont helm: "With her profile, she could be in the way." Would she find difficulty in adapting to the new regime?

"One minute she's a Tsar, ruling by decree, the next she's preparing to divest her power," says one soon-to-be Assemblyman.

How would she handle proposals or plans from the emergent administration which might run counter to British government thinking or policy? Might she seek to overrule shadow ministers in the potentially crucial area of civil service appointments?

How, indeed, would the civil service react - torn between their Secretary of State and their new political masters?

One shrewd observer of this scene draws a comparison with the unfolding constitutional developments in Scotland where Donald Dewar hopes shortly to become First Minister in the new Scottish Parliament. Would he enjoy having his transition period presided over by someone like Robin Cook? "It could all prove very disruptive," suggests this source, arguing for a replacement Secretary of State: "someone with a lower profile who can let the new administration find its feet and grab hold of the system."

But who? One name being canvassed is John Reid, a sound level-headed fellow currently number two at the Ministry of Defence. Another is Paul Murphy, the Political Development Minister at Stormont, widely considered a "safe pair of hands" who has made no obvious enemies. Some nationalist politicians, however, question whether he carries the necessary political weight.

Too much weight, or too little? Stormont - backwater for the dull but competent, or staging post for someone working his way up the ministerial ladder? These, as all the local politicians are swift to acknowledge, are for decision by Mr Blair. He probably doesn't know yet.

Dr Mowlam will be the first to hear when he does. And she will know that, for all the bruising they've given her, when she goes - as assuredly she will now or next spring - the locals will finally find nice things to say about her.