Prime Ministers are seen as presidential figures, so mighty they act more or less as they please. Shelves creak with books arguing earnestly that their powers are close to being dictatorial. A consequence of Gordon Brown's premiership is that a new shelf must be found for authors making the opposite case. Brown was much more powerful on every front when he was Chancellor than he has been as Prime Minister.
Take the recent ministerial assertiveness over who is in charge of the forthcoming election campaign. Before Brown became Prime Minister there were few rows about who would run an election campaign for Labour. Ministers from Tony Blair downwards accepted that only one figure ran election strategy. That figure was Brown. Even when Blair sought to make Brown more marginal in the build-up to the 2005 election he did not succeed. In the end Brown, the Chancellor, was in charge then, as he was in 1997 and 2001. Working closely with his entourage he set the terms of the campaigns.
If Brown wanted a campaign about "investment versus cuts" and other similar dividing lines that was the campaign he got. There might have been some dissenting whispers but they were soon swept aside by a Chancellor who had the power to run the economy and simultaneously mastermind elections almost single-handedly.
Now merely a Prime Minister, Brown has to listen to other ministers as they express their concerns and demand to be involved. He has been forced to give some ministers key roles whether he wants to do so or not. Indeed there are so many ministers suddenly directly involved in the campaign planning it is a miracle any governing is being done at all. Three of them were lined up to address Labour MPs at the post coup meeting of PLP last night.
Peter Mandelson, Harriet Harman and Douglas Alexander are all in charge of the forthcoming campaign. Each of them in their different ways have made clear that they were not happy with the direction of Brown's leadership and, specifically, the erratic, chaotic early election planning, as far as that planning could be discerned.
Harman flexed her muscles in that significant lull after the attempted coup last Wednesday, the hours before some cabinet ministers declared their support. Alexander was another who chose not to issue a statement right away. Now they assert the importance of the ministerial team in the build-up to the election. Mandelson and Alexander had four phone calls on Sunday to discuss the election campaign. Contrary to some reports the two of them work together well.
Even so, by instinct Brown would probably much prefer to make his strategic moves in the build-up to the election unimpeded, after a discussion with Ed Balls, as he did in 1997, 2001 and 2005. He is not powerful enough to do so now. Instead he must dance weakly to the tunes of what appears to be an entire orchestra of election strategists.
Elsewhere he dances to other suddenly assertive players. Economic policy-making defines a government and the pitch of a party at election time. As shadow Chancellor and then Chancellor Brown had the terrain more or less to himself. If he wanted to highlight "affordable tax cuts" he did so. If he thought investment should be the theme it became the theme of the entire government.
Even Blair did not know what was in some of Brown's budgets. For years other ministers did not dare to think about economic policy, let alone utter a public word on the subject. Now he is Prime Minister, Brown's powers are constrained. The Chancellor, Alistair Darling, felt strong enough after his exchange with Brown on the afternoon of the attempted coup to give an interview to The Times on Saturday in which he focused on the "toughest public spending round in 20 years". A few days earlier Brown had given an interview in which he had stressed investment priorities. He is not powerful enough to hold the presentational line. If Darling wanted to announced a spending cut a day he could do so now. Darling cannot be sacked this side of the election.
As a mighty Chancellor, Brown had a big say in who got what job and who did not. If he disapproved of a ministerial appointment he made sure that his or her space for manoeuvre was limited. When Blair elevated the likes of Mandelson and Alan Milburn in cabinet reshuffles Brown despaired. As one of his close allies told me, "Tony's reshuffles were highly charged affairs as far as Gordon was concerned". In particular he needed to lie down in a darkened room when Blair promoted Mandelson to be President of the Board of Trade in 1998. Even so, once Brown had recovered from the shock he was so powerful as Chancellor he made sure Mandelson had no space to put the case for the euro or to say very much on the economy.
With an almost comical symmetry, as Prime Minister he was so weak he buttressed his precarious perch by giving Mandelson a more wide-ranging and powerful portfolio than Blair would ever have dared to offer his friend. During an earlier crisis Brown also discussed with Milburn the possibility of a return. Since becoming Prime Minister his powers are so diminished that his enemies have flourished more than they did when he was Chancellor. In contrast, even before last Wednesday Brown was not powerful enough to make Ed Balls Chancellor, although he is the figure whose judgement he rates above all others.
As Prime Minister he finally acquired formal powers of patronage. Yet he was able to hand out more jobs to his allies when he was Chancellor and he had no formal powers at all.
That was partly because when he was Chancellor he had significant, authority enhancing sections of support in the media. In No 10 The Guardian was nicknamed the Gordian, such was the intensity of Brownite support. Now the paper has called for him to go. "He has no constituency in the media", observes one cabinet colleague who remembers the era when a range of newspapers paid homage.
Brown will lead Labour into the election. He will never enjoy the immense power he wielded at the Treasury when he yearned, every minute of each day, to make the move to No 10.