Whatever is ailing Martin McGuinness is serious, for now, and has political implications which can not be ignored, however indelicate it seems to mention that fact.

Arlene Foster has suggested that one feature of the current political crisis was that senior members of Sinn Fein were jockeying for position in the knowledge that the Deputy First Minister was seriously ill. She was reviled on social media for "bad taste".

And it would be a pity if she really believed that her political problems were not substantially of her own making.

It also seems unlikely that Sinn Fein will have much of a contest for the new northern leadership. That appointment will be made by Gerry Adams and a few close advisors.

Yet it is legitimate to speculate on who they might choose.

The speculation among journalists and commentators would probably light on Conor Murphy as the favourite.

Murphy has several advantages. For one, he was in the IRA. This may still count for something. Just a year ago a security assessment for the Executive said that many in the IRA believed they still controlled Sinn Fein, and while Sinn Fein denies that, disabusing the army council of that delusion may bring some discomfort. On the other hand, this may be exactly the right time to appoint someone with no paramilitary past.

That might soothe relations with the DUP, yet Murphy worked alongside Arlene Foster in the same office building in Adelaide Street and they got on well.

Murphy might also bring baggage with him. He told Jeremy Paxman on Newsnight, when he was a minister, that he had spoken to the IRA and confirmed with them that they had not killed Paul Quinn in 2007. This could rebound on him as collusion in a massive lie. It has echoes of the problem that Gerry Adams faces in the South. He met an IRA member with the sons of murder victim Brian Stack and is under pressure now to assist the investigation by naming that contact and he is refusing to comply.

Might Mairtin O Muilleoir be the next DFM? He is seen as being both clever and charismatic. He has no IRA record and he is hugely personable on the media, as well as having international contacts and a proven record of achievement. If he is not a serious contender, then Sinn Fein is not a normal party yet.

Michelle Gildernew has been a minister and an MP, albeit an abstainer. She has the intelligence and the charm.

But she has embarrassed the party a couple of times, once by writing candidly about how being shifted from the Assembly had triggered depression, and once by speaking in support of disgraced business man Sean Quinn.

Then there is John O'Dowd, a former education minister who handled his brief assertively while, at the same time, preferring colloquial to textbook grammar. He took over as Deputy First Minister from Martin McGuinness when McGuinness was contesting the 2012 presidential election. That surely is some degree of endorsement of him as fit for the role. And there is no IRA record there.

Yet Adams and his coterie may cast wider for a replacement in the event of Martin McGuinness standing down to preserve his health. The appointee may not even be a northerner or even have won a seat to the Assembly.

Another MLA might be asked to stand down to make room for, say, Pearse Doherty or even Mary Lou McDonald.

Here are two brilliant politicians at the very top of the party whose advance towards the leadership is still blocked by the incumbent Gerry Adams's fondness for the job.

It might seem unlikely, but it is not impossible that either would be sent North given the importance of retaining the all island character of the party.

The danger of having separate leadership structures on each side of the border, drifting further apart as old leaders move on, is that Sinn Fein would be a partitioned party, organic evidence of the inevitability of the very evil they exist to oppose, partition.

Mary Lou might not be keen on the job, but she has been at Adams's side in the North during past talks processes.

Or Adams might even take the job himself.

That would extract him from the routine horror of being mocked in the Dail by Fianna Fail, which is determined to beat back competition from Sinn Fein for the Republican vote.

But currently no vacancy exists, and given the difficulty of the choice, Adams and others might be thinking back to the marvellous recovery that Ian Paisley made from an illness that seemed likely to end his career - and wishing similar blessings upon the head of Martin McGuinness.

Belfast Telegraph