By David Thompson
BBC News political correspondent
Mr Brown has faced criticism since he has been in the US
It must have seemed like a good idea at the time.
Parliament in recess, things pretty gloomy at home - what better time to go to America and be seen as a player on the world stage?
Well, forget the fact that Gordon Brown has been largely upstaged in the US by the Pope. The prime minister could probably live with that.
What must hurt is that, while the cat's away, the mice have decided to play.
A string of senior Labour figures have chosen this week to put the boot into Gordon Brown.
David Blunkett, the former home secretary, spoke out against scrapping the 10p income tax band, urging Mr Brown to help those most affected by it.
He was followed by Alistair Darling, who said the government needed to sharpen up, make a better fist of explaining to voters exactly what it was all about.
It was an unexpectedly forceful admission from the chancellor that the government needed to raise its game.
Then came Lord Desai.
He decided to tell the Evening Standard that "Gordon Brown was put on earth to remind people how good Tony Blair was", that his style was "porridge, or maybe haggis" and explained to News 24 that he wasn't stabbing the Prime Minister in the back.
He was stabbing him in the front.
And, after that, came the strange saga of ministerial aide Angela Smith, who appeared to have resigned from the government over the abolition of the 10p income tax rate. It was later announced by Downing Street that she had not gone after all.
On their own, any one of these news items wouldn't matter very much.
Lord Desai is an eminent economist, but by no means a rebel and also perhaps not politically savvy enough to have realised the impact his words would have.
Angela Smith is hardly a household name. On its own, her resignation - or non-resignation - would barely cause a ripple in the Westminster goldfish bowl.
And, with Labour trailing so badly in the polls, Alistair Darling's words could be seen as a statement of the obvious.
What makes them significant is two things. One, that Labour's self-discipline, once the thing that made it the most feared political operation in Westminster, seems to have been mislaid. Remember when the most important thing for a Labour MP to be was "on-message"? That seems like a long time ago now.
Two, that the real problem for Gordon Brown is less what people are saying but more, perhaps, that they're saying what a lot of Labour Party members are thinking.
All governments go through rough patches, all prime ministers have spells of unpopularity.
A rash of bad headlines and the grumblings of an anxious party do not necessarily an election defeat make, especially when that election may be as much as two years away.
Harold MacMillan once said the thing most likely to blow a government off-course were, "events, dear boy, events", and Gordon Brown has had to contend with a whole series of those, ranging from terror attacks to a global financial meltdown.
But the decision to abolish the 10p tax band was his and, ultimately, responsibility for the mood of the Labour Party largely rests with its leader.
The past week has given some Labour politicians you've never heard of a brief outing in the sun.
But as he flies back from America, Gordon Brown will know his party has to rediscover self-discipline - and that he has to rediscover a way of inspiring it once again.