Labour and the turbulent priests
The Labour First Minister and the leading Roman Catholic in Scotland were getting on well, and so they should have, given the support Scottish Catholics have given the Labour Party over the past 100 years.
But beneath the surface, the relationship is more fractious and difficult than it has been for at least a generation.
The fault-line was exposed by the Bishop of Motherwell, the Rt Rev Joseph Devine, who spoke out against Labour just as Mr McConnell and Cardinal O'Brien were chatting at Celtic Park.
Rt Rev Devine said he would not be voting Labour in May and warned the allegiance of many other Catholics to the party was being "severely tested" to breaking point.
The bishop's intervention is not a lone cry. Several other senior Catholics are understood to be preparing to speak out, and a pastoral letter, to be read out in Catholic churches before the election, is being prepared.
It is not known how critical this letter will be, but it is unlikely to give Labour the ringing endorsement the party would like.
It follows the row over gay adoption earlier this year, when the Catholic Church in Scotland threatened legal action to block the anti-discrimination laws, which, it claimed, would force faith-based adoption agencies to close.
And late last year Cardinal O'Brien infuriated Labour figures by saying he would be "happy" if Scotland became independent.
All these flashpoints suggest the traditionally close relationship between the Catholic Church and the Scottish Labour Party appears to be fragmenting just when Labour needs it most.
So how bad is it?
Rt Rev Devine said he would probably vote for the Christian People's Alliance in May, a small and little-known organisation standing for family values and Christian ethics.
Political experts said last night Rt Rev Devine's intervention would probably do little to help the CPA, but it symbolised a disintegration of Labour's core vote.
James Mitchell, a professor at Strathclyde University's department of government, said: "There has been a long process of change in the Catholic vote in Scotland. In the 1970s, it was overwhelmingly Labour. By 1992, there had been a shift, and a number started voting SNP, particularly young, male, working-class Catholics."
Prof Mitchell said Labour used to rely on a series of overlapping groups - people who unionised, industrialised, rented council houses and were Catholic - but that Labour's hold on all these had been disintegrating.
He added that the current evidence of disillusionment within the Catholic community was symptomatic of that process, and it was an issue Labour had to address.
Peter Lynch, a senior lecturer in politics at Stirling University, agreed the CPA would make no impact at the election. But, he said: "What is interesting is what it says about Labour voters. It doesn't mean a huge transition of support, but it suggests some of the Labour vote will fragment and other parts will stay at home."
Mr Lynch said he expected the SNP to gain some votes from disillusionment with Labour and the CPA to pick up a small number, but many other voters to stay at home.
The attitude of most Labour MSPs seems to be resigned frustration at Rt Rev Devine's comments, rather than any anger at senior church figures getting involved in politics so directly.
One Catholic Labour MSP said: "They have been getting involved in politics since time immemorial. You can't stop them."
And asked whether the bishop's comments would harm Labour at the polls, the MSP replied: "I don't think so."
It is true that senior church figures have been causing problems for the ruling classes in Scotland for hundreds of years, not least John Knox.
However, this present-day spat has brought into focus the tension among Christian socialists between socially progressive policies and moral conservatism.
The Christian People's Alliance is the embodiment of that tension and what happens when Labour supporters can no longer reconcile the two divergent approaches.
The Scottish arm of the CPA was set up by Teresa Smith, a former local Labour office-holder.
On one side, the CPA endorses many traditional left-wing policies - it is against the replacement of Trident and the Iraq war; it is in favour of free school meals for all and the alleviation of poverty through government action.
However, the CPA is also staunchly anti-abortion and pro-family, attacking not only the Executive's introduction of so-called "quickie divorces" and gay adoption, but also proposals to liberalise the teaching of homosexuality in schools.
On the surface, the arrival of a religious group on the Scottish electoral scene might spark comparisons with the United States and the influence of the Christian Right on US politics.
But the situation in Scotland is very different. Ms Smith bridles at any suggestion that her organisation is anything like the Christian Right.
Her role models all come from northern Europe, where Christian democratic parties have made modest and, in some cases, respectable progress.
"We are not at all like the American scene," she said. "We were the first party in Britain to vote against the Iraq war, we are vociferously opposed to the replacement of Trident and we have good policies on poverty."
Ms Smith also takes issue with political experts who claim the CPA will make no progress in May.
She said a return of one MSP was realistic, while two would be a momentous victory for the party.
The CPA has been going in Scotland only since 2000, but this year, for the first time, it will stand candidates in every part of the country.
Ms Smith stated: "In the past four years in particular, Labour and the Liberal Democrats, who are the ruling partners in this parliament, have abandoned any pretence of looking after the family or to have any moral principles; they are becoming increasingly secular."
Labour has indeed become increasingly secular, reflecting a more general change in society as a whole.
There will be some Labour supporters who will stay at home on 3 May, angry at the party's approach to moral issues. Others will vote SNP, and some may even support the CPA.
But Labour leaders realise the party would sacrifice far more of its support if it embraced the sort of unwavering moral approach Rt Rev Devine would like.
Christian alliance with an emphasis on pro-life issues
THE Christian People's Alliance Scotland was formed in 2001, but this year will be the first time it has put up candidates in all parts of the country.
Teresa Smith is its chair, and a member of the CPA council in the UK. A former psychologist, she said she now works "24/7" for the CPA and will be standing as its leading candidate on its Central Scotland list. She was previously an active member of the Labour Party, chairing various committees in her Dumfries constituency until she left in 2000, disillusioned with the party's approach to moral matters, particularly the family and abortion.
Like many in the CPA, Ms Smith is very active in Church matters. Married with a daughter, she is passionate about her organisation's approach and vociferous in her condemnation of the "secular" approaches that the main parties take to policy.
Ms Smith also chairs the Pastoral Council of the UK CPA and she has completed a Diploma for Pastoral Ministry.
However, she was keen to stress that members of the CPA did not have to be Christians, as long as they supported the central tenets of the CPA's message - pro-life, pro-family, pro-environment and anti-nuclear weapons. This is shown by the organisation's leading candidate for Glasgow, Abdul Dean, who is a Muslim but who agrees with the CPA's core message.
Some of the CPA's leading candidates come from a pro-life background. Ms Smith lists one of her main interests as "pro-life issues", and Robert Rogers, expected to be another of the CPA's leading candidates, also comes with a strong pro-life agenda.