Peter Robinson and Martin McGuinness present united front on US trip

Mingling with Irish Americans in a tiny penthouse garden area at the top of Fitzpatrick's Manhattan hotel, Peter Robinson and Martin McGuinness were among friends and believers.

Duncan Niederauer from the New York Stock Exchange has just been given a CBE for his contribution in bringing hundreds of jobs to Belfast. He acknowledged it has been a difficult summer for Northern Ireland, but put that down as a short-term blip against a pattern of long-term progress.

Mr Niederauer wasn't exercised about the first and deputy first minister's Maze peace centre dispute, arguing that New Yorkers are well used to their own politicians falling out from time to time.

The wealthy philanthropist Loretta Brennan Glucksmann is retiring as chair of the American Ireland Fund.

She went so far as to praise the chemistry between Mr Robinson and Mr McGuinness and to predict they will lead Northern Ireland on to better times.

So is the summer falling out between Stormont's top two sorted? Don't believe it.

The deputy first minister has very deliberately avoided a slanging match, but under the surface he's still seething about the DUP leader's decision to put the peace centre on hold.

With existing and potential investors to be sweet talked, both Messrs Robinson and McGuinness are mature enough to show unity and get on with their joint sales pitch.

Not only that, neither leader wants to appear negative ahead of next week's Haass talks in Belfast.

Despite this temporary New York truce, keep a watch on two fronts.

Will Sinn Féin block any economic development on the wider Maze site unless and until the peace centre project is revived?

And will the row spill out into any other policy areas (welfare reform?) requiring co-operation between Stormont's two biggest parties?