The current war of words between the SDLP and Sinn Fein must be seen in perspective. It is not the end of the peace process or of the Hume-Adams political relationship. But it does bring home the fact that for all their common interests the two parties are also competitors.
It is not generally known that the SDLP leader, Mr John Hume, was once a businessman-in-the-making and had the distinction of being one of the first people to come up with the idea of selling bottled water on the home market. But for the Troubles he would probably have been a highly-successful entrepreneur.
The relationship between the SDLP and Sinn Fein could be compared to that between two companies distributing bottled water. Both have an interest in maintaining the purity of the water supply, but that does not lessen their rivalry to be the first one picked out by the customer from the supermarket shelf.
Similarly, the SDLP and Sinn Fein leaderships have a common interest in maintaining the IRA ceasefire while at the same time engaging in a fierce contest for the nationalist vote.
Talks insiders remarked that, far from being a sign of danger for the peace process, the latest skirmishing shows that push is coming to shove. There is a deal in the making and parties are being forced to define their positions more clearly than before.
Senior SDLP sources stressed they did not see the dispute as a party-political issue. "We have been disappointed in the way Sinn Fein has sought to personalise it." Sinn Fein's approach in seeking to isolate the SDLP deputy leader, Mr Seamus Mallon, as the cause of the problem is reminiscent of the party's strategy during the Westminster elections. The immediate consequence of this was a brief statement yesterday from Mr Hume defending his "friend and colleague".
There is a rude name in the American political lexicon for this type of slanging match in which both parties end up suffering as much damage as they inflict. It is understood that Sinn Fein is now about to turn down the heat, even though there are elements in both parties that are spoiling for a fight.
Indeed Sinn Fein sources said last night they were not interested in trying to split the SDLP or drive a wedge between Mr Hume and Mr Mallon, as this would be contrary to republican peace strategy.
They were simply responding to public and private criticism by Mr Mallon including "ferocious and scathing" attacks on them at the talks table.
But while the sound of hostilities may die down, the basic conflict remains unresolved. As chief negotiator for the SDLP, Mr Mallon has assumed a more central role than before in the life of the party. His role could be compared to a prime minister, with Mr Hume cast as president.
Mr Mallon famously described the current process as "Sunning dale for slow learners". It stung Sinn Fein at the time but may now come back to haunt him, with the republicans using it as evidence that he is selling the nationalist community short on the issue of a Northern assembly.
The unanswered question is where the soul of the nationalist community lies. Long-time SDLP activists confided yesterday that they were unsure whose approach would win most support at the polls. The test might not be long coming: the two governments are blowing everyone down with their hurricane of optimism that a referendum on a settlement package will go ahead in May.
In that case, an election to a regional body of some kind, whether it is called an assembly or by some carefully-chosen euphemism, could very well be held in the autumn.
"Sinn Fein is streets ahead in the media," a hardened SDLP campaigner lamented. Thanks to the SDLP's efforts, nationalists were making inroads to the Northern middle class, but there was a danger that telegenic Sinn Fein representatives would scoop up that vote.
The recent Omagh District Council by-election saw SDLP support drop by 510 votes. Some of these clearly went to Sinn Fein who won the seat, but others stayed at home. SDLP sources said the area was a republican heartland and that on this occasion the nationalist middle class had stayed at home. Sinn Fein interpreted the vote as a resounding endorsement of its strategy.
There have been taunts about SDLP attempts to replace the Hume-Adams agreement with a Mallon-Trimble pact. But SDLP supporters argue this is the inevitable shape of any agreement likely to come out of the current talks and that Mr Mallon is more realistic than Sinn Fein on what the Ulster Unionists are prepared to accept.
Privately, Sinn Fein figures sneer that "the SDLP will settle for anything". But other observers believe the Great Helmsman from Derry, John Hume, is keeping the nationalist ship on course, undeflected by an outbreak of squabbling among the crew. In this analysis, his defence of Mr Mallon was measured and dignified: enough to bring Sinn Fein back into line but without engendering a break with Mr Gerry Adams.
Unionists can at least take a breather from their own internal troubles to enjoy the sight of nationalists at each other's throats.
The current anxiety in the UUP appears to be the possibility that the party delegation at the White House on St Patrick's Day might be curtailed as a result of IrishAmerican lobbying: the IrishAmerican view is that the UUP should pay a price for not engaging more fully in the talks. The White House has not announced a decision but it appears that there may be a reduction in the numbers admitted from all the parties in the talks.
Already UUP sources are muttering darkly about not having a welcome for President Clinton should he decide to visit Belfast in May. This is the old Ulster game of "getting your retaliation in first".