With thousands of decisions taken in government every day, unless there is that sense of purpose, Ministers and the people who support them will simply go their own way. And the whole will be far less than the sum of the parts.
This is particularly true when it comes to the incredibly complex task of running the state and public services. Millions of choices are made each year in these organisations.
Even the most hands-on Prime Minister cannot determine those choices, nor should they want to.
But a Prime Minister and a government can establish a culture for the way public services ought to work. My case is that the time demands a new culture in our public services.
The challenges facing public services are just too complex to deliver in an old-fashioned, top-down way without the active engagement of the patient, the pupil or the parent: from mental health, to autism, to care for the elderly, to giving kids the best start in the early years.
So what are the principles that should guide us in tackling inequalities of power and improving public services?
First, we should change the assumption about who owns access to information because information is power. And if we care about unequal power, we should care about unequal access to information.
From schools to the NHS to local government, there is an extraordinary amount of information about users of public services.
But the working assumption is still that people only get access to it when the professionals say it is okay or when people make a legal request.
Our assumption should be the opposite. That information on individuals should be owned by and accessible to the individual, not hoarded by the state.
But information is not enough if we are going to tackle the inequalities of power that people face.
My second principle is that no user of public services should be left as an isolated individual, but should be able to link up with others.
The old assumption is that success in public services comes from the professional delivering directly to the single user. In fact, there is now a wealth of evidence that the quality of people’s social networks with other patients, parents and service users can make a all the difference to the success of the service.
Nothing makes people feel more vulnerable than having to stand on their own, confronted with a vast and complex world of services that they can’t make sense of or options they don’t understand.
But if we are truly to make our public services open to the voices of those they are meant to serve, we need to throw the decision-making structures open to people too.
So my third principle is that every user of a public service has something to contribute and the presumption should be that decisions should be made by users and public servants together, and not public servants on their own.
Of course, this is what so many great public services already do.
Personal budgets have allowed many disabled people to shape the services that matter for them, working hand-in-hand with public service professionals.
Having promised to share power, this government has actually centralised power in Whitehall, attempting to run thousands of schools from there.
And as a result some schools have been left to fail. Just last week we saw the Al-Madinah School in Derby close, because its failings were spotted far too late. Clearly, we need greater local accountability for our schools.
Parents should not have to wait for some other body to intervene if they have serious concerns about how their school is doing, whether it is a free school, academy or local authority school. But at the moment they do.
In all schools, there should be a “parent call-in”, where a significant number of parents can come together and call for immediate action on standards.
The fourth principle is that it is right to devolve power down not just to the user but to the local level. The centralised state cannot diagnose and solve every local problem from Whitehall.
In all of these public services, we are determined to drive power down. This devolution of power is the right thing to do for the users of public services and is the right way to show that we can do more with less.
I know that we are putting the right issues at the heart of our programme.
And we are standing where the British people stand. They want a government that will stand up for them against unaccountable power, wherever it is.
Ed Miliband is the leader of the Labour Party and MP for Doncaster North. This is an edited extract from his Hugo Young Lecture.