Roger Liddle: Labour must prevent the disaster of a referendum defeat

Labour cannot afford to let the case for Europe go by default. Lose on Europe and we lose one of the crucial progressive platforms for the advance of modern social democracy.

Labour cannot afford to let the case for Europe go by default. Lose on Europe and we lose one of the crucial progressive platforms for the advance of modern social democracy.

A referendum defeat would be an unmitigated political disaster. Far from taking the troublesome issue of Europe off the political agenda, it would make the future of Britain's relations with Europe the central abiding preoccupation of Labour's third term. A "No" would be a huge advance for the forces of the right: the closet "withdrawalists" who cynically regard the referendum as the first step in a two-stage process to detach Britain from Europe.

It is no good hoping this difficult issue will somehow go away. It won't. Any club needs rules that govern those who choose to be its members. The rules for membership of the enlarged club now need to be settled for the foreseeable future.

The constitutional treaty enshrines the transformation of Europe from a single market to a political Union, albeit radically different from a Federal United States of Europe because the member states play the defining role. Some of our partners ruefully refer to this as "La constitution Britannique". Yet, somehow, we British pro-Europeans find it difficult to make the case.

The worst argument for the treaty is to focus on what it isn't, rather than what it is. "Fear not, we have held back the Eurofederalist hordes that threaten our shores". This feeds the suspicion that Europe is a conspiracy against our patriotic interests, and is hardly a convincing backcloth to the argument that a Britain, fully committed to the European Union, can play a leading role within it.

Europe cannot simply be explained to the British people as a "free trade area" vital to our prosperity. We cannot continue to peddle what first became the establishment consensus under Macmillan, that there was "no alternative", with each step in European integration presented as both "inevitable" and constitutionally insignificant. The significance of building a new potential for political action "beyond the nation state" has to be justified, not underplayed.

Progressives should argue for the constitutional treaty on its merits. To the running of Europe, it will bring greater clarity, greater effectiveness and greater democracy. The provisions of the treaty embed values, objectives and fundamental rights that every progressive constituency should embrace with enthusiasm.

Social democrats should make a bold progressive argument for Europe. Without the full potential of the single market, Labour's ability to sustain high public spending and high-quality public services will be impaired. Secondly, separated from the EU, Britain would cut its ties to a "social market" model for economic development which embeds values and a framework of rules that promote social justice and environmental sustainability. We would cease to be bound into a distinctive European model for growth: the only available modern alternative to the post-war model of nation state social democracy that is now unrealistic.

Third, outside the EU, Britain would stand alone, in a world where China, India and Brazil emerge as economic powers. We may convince ourselves that a New Labour Britain represents a uniquely successful model of progressive advance, but outside the EU, we lose our capacity to multiply our influence, shape globalisation and be an effective force for good in the world.

A realistic progressive goal is to build a more equal partnership between a more united and effective Europe and a genuinely internationalist United States. But for Europe to be a credible provider of security in the "arc of instability" that surrounds us, never mind aspire to a more equal transatlantic partnership, poses multiple challenges: to traditional German reluctance to contemplate the use of force, to French illusions of a multipolar world and to British conceptions of a special relationship with the US. Britain will have to adapt to a new conception of its role as a US-friendly partner within the European camp, rather than as a transatlantic "bridge".

General election night will fire the gun for the start of the European referendum campaign. The Labour Party must be confident of its pro-European values. It must insist the party's collective leadership stands up for them. While it is possible to be pro-European in the modern world without being on the left, it is impossible to be on the progressive left without being a pro-European. Alongside the advance of the domestic "progressive consensus" that New Labour has created, victory in the referendum will be the third term fulfilment of the Blair premiership and we would, in the process, achieve an irreversible shift towards a more social-democratic Britain.

The author was Tony Blair's policy adviser on Europe, 1997-2004 and is a member of the cabinet of the European Trade Commissioner, Peter Mandelson. His 'The New Case for Europe' is published by the Fabian Society'