Two memories from the summer will inspire and sustain me during the months ahead. The first was a day of affirmation and hope when, along with 200,000 others, I marched to "make poverty history". The second was a day of sadness and remembering when I gathered with hundreds of other mourners to celebrate the life and service of Robin Cook. One was a rally, the other a funeral. What for me unites these two very different days is that they both challenged the notion that politics and public activism are a mug's game.
These events cast a different light on the public realm at a time of frustration and hostility towards party politics and politicians. Labour has to acknowledge the scale of the challenge that the public mood presents. Civic activism is flourishing as political activism falters. The four largest development charities have more supporters than the combined membership of the three main parties. While we celebrate, at the Labour party conference, an unprecedented third-term victory, our membership has been declining for some time and participation is decreasing with it. Research suggests that while half of our members took part in campaigning in 1991, by 1999 this figure had fallen to less than a third.
These facts make for uncomfortable reading. Yet they ring true to those of us who were campaigning in marginal and heartland seats across the country at the last general election. Some will claim that they can be explained wholly by Iraq. I would argue that, at a much more fundamental level, they reveal how a party of power must now not only consolidate but strengthen its hold on the "common sense" of its times. With 40 "super-marginals", an ongoing Liberal Democrat challenge and a new Conservative leader in prospect, we have no time to waste.
The US provides a telling contrast. The right there has created a uniquely powerful political movement. It has its own think-tanks, sources of money and local organisations, as well as its own radio stations and TV channels. This is more than a matter of resources or structures. The Republicans have found a unifying ideology that has brought together an otherwise diverse coalition of evangelical Christians, gun owners, blue-collar workers and corporate business. This shows how the purpose of politics is not simply to inhabit the centre ground of public opinion. The point for Labour is to shift it, consciously and irrevocably, towards our vision of a good society. The Republicans understand that, but so, too, does the Thatcherite right in the UK. That is why Edward Leigh, the Tory MP, wrote recently: "We must seize the centre ground and pull it kicking and screaming towards us."
If we do not act now to strengthen our party, the voice for progressive change within British society will be diminished. Of all people, Robin Cook understood why this mattered. Robin passionately believed that a Labour government should not just accommodate the times but should transform them. He understood that politics can often be a matter of compromise, but he never gave up his commitment to the Labour movement as the vehicle by which a progressive future could be achieved for our nation. Shortly before his death, he wrote: "The paradigm shift that Labour needs cannot be achieved by one member, but needs the contribution of all."
None of us would ever wish to go back to the corrosive divisions between government and party that so weakened previous Labour administrations. Yet the contribution party members can make is a vital ingredient of further policy and political progress. The principles of empowerment and local participation explain the success of initiatives such as Sure Start. It is these very same principles that must now guide the process of party renewal.
In Labour's first term, our mission was to secure support for the economic prosperity integral to a socially just society. In our second term, we fought for - and won - the case for investment in public services. It is clear now that our next task is not just to protect these victories, but to press home our advantage.
The falling levels of child and pensioner poverty alone since 1997 demonstrate that Labour has made real advances. Indeed, the fact that infant mortality has increased in America since 2000 is a stark reminder of the choices that governments can make. While infant mortality has declined in the UK since 1997, it is still more likely to affect poorer families in our society. If we are to build on our achievements so far, we need a progressive movement that can articulate why the cost to our society of poverty, inequality and disadvantage is one which we all bear. It is our duty to make the case for the policies that break the link between where a child comes from and what he or she achieves.
To translate these progressive impulses into a progressive movement requires us to be on doorsteps, at school gates, in community groups and online, speaking up for social justice. Although civic and charitable activism can challenge the results of inequality, it is only through party political activism that we can demand an end to its causes. A truly progressive Britain needs both if our vision of the "good society" is to be realised.
In pursuit of such an ambition, economic competence is a vital and necessary, yet insufficient, motor for social justice, even when enacted with egalitarian aims. Indeed, we must acknowledge that extending economic opportunity to all is only one aspect of the progressive vision of Britain to which we aspire. Ours is a political movement with ambitions to fashion a different kind of society.
In power, we have made inroads into the economic instability and poverty that blighted Britain's dreams during the Thatcher years. However, the purpose of our party should not only be about getting progressive governments elected to repair the damage caused by our Conservative predecessors. We must also uphold the role that members can make as advocates for social change within their own communities.
The vast majority of us struggling with the everyday dilemmas that life brings want our lives to have meaning beyond the hollow claims of consumerism. In the personal realm, most of us want more from life than isolation and acquisition. We try to do the best by family, friends and neighbours, and to balance the material and the non-material sides of life. We know that it is only in partnership with those who share our progressive instincts across the country that we can foster a culture of reciprocity and responsibility. Building social cohesion requires public expression of those progressive impulses that are at present too often confined to private concerns.
In the months and years ahead, our politics must do more than make the case for removing the barriers to achievement that scar society. It requires us to set out our vision of a progressive nation in a way that can offer inspiration for our party and can help build a society that is more receptive to progressive change - a vision which offers all of us a more hopeful way to live.
Douglas Alexander is Labour MP for Paisley and Renfrewshire South and minister for Europe