Berlusconi does it again. Zapatero zaps the conservatives. Will it be Boris or Ken for mayor of London? Europe, where democracy was invented 25 centuries ago, is now a hotbed of it. Messy, often corrupt, distorted by media ownership, sometimes disconcerting in its outcomes - Berlusconi! - but still definitely democracy, a system in which the people can change the government. Not a month goes by without an election somewhere in Europe. And you never know who's going to win.

What the ancient Athenians called demokratia may be old, but for most Europeans the reality is new: half today's European states have enjoyed consolidated liberal democracy for less than a generation. And from Portugal to Croatia, the prospect and process of joining the EU have strengthened democracy in country after country. This has been, and for a few candidate countries still is, Europe's transformative power - more effective in securing regime change than any army.

Now a great idea is stalking the corridors of Europe. It is that Europeans should resolve to promote a modern, liberal version of demokratia in countries beyond Europe's borders - in our own interest, and in theirs. This should become a central purpose of the European project for the next 50 years. Not imposing a single model of democracy by military means and not "exporting" democracy, but supporting it, by peaceful means. "Showing the way does not mean imposing the way," as European commission president José Manuel Barroso said earlier this week, at the launch of a new, non-governmental European Foundation for Democracy through Partnership.

To make this happen, we have first to agree among ourselves that this is what we want to do. That may sound obvious, but it's not. Many people, particularly on the European left, somehow feel the idea of "democracy promotion" is tainted by its association with George Bush and a neoconservative vision for the transformation of the Middle East. Until recently, French, Spanish and German socialists spoke very little about promoting democracy. This is changing, especially as the debate about development has increasingly focused on good governance, but we still need to make the explicit commitment, across all parties.

Then we need to say what we mean by democracy. After all, everyone pays lip service to it: the Egyptians, the Chinese, Vladimir Putin, Robert Mugabe. But they mean something different. This does not and cannot imply a single rigid template. Europe is immunised against what one might call the American temptation by the simple fact that Europe's democracies are themselves so diverse: constitutional monarchies and republics, unicameral and bicameral, centralised and decentralised, with a strong executive and weaker legislature, or vice versa. We can hardly propagate a single model when we have none ourselves. All the more reason, however, to spell out the shared essentials without which there is no democracy worthy of the name. That does not just mean regular, free and fair elections. The emerging European definition of democracy will be multidimensional, including the rule of law, independent media, respect for both individual human rights and minority rights, sound public administration, civilian control over the military and a strong civil society. (Yes, I know, not all EU member states themselves score well on all these points - a subject to which I'll return.)

In the framework of the EU, these two things - saying what we want, and what we mean by it - can best be done through promulgating a European consensus on democracy, like the European Consensus on Development passed a few years ago. In that pioneering document, the member states, the European parliament, the European commission and the Council of Ministers all agreed what we meant by development and how we should best work to promote it.

Now a proposal is before the European parliament suggesting we do the same for democracy. Several governments support the idea, and the three upcoming half-year EU presidencies should be interested: the French, especially with veteran human rights activist Bernard Kouchner as foreign minister, the Swedes, and the Czechs, who have a vivid, recent memory of what a difference it made to be helped to democracy. And the proposal will find stalwart friends in Javier Solana and Barroso, who actively participated in their countries' transition to democracy.

The devil will, as always, be in the detail. The text must avoid, at all costs, those characteristic EU afflictions: waffle and fudge. Yet there's some uncharacteristically clear and robust language around already, in existing European documents, including those from the development aid side, where Europe spends bigger bucks than anyone. Then, however, it's a matter of practising what we preach. Who will do it and how? We know the answer for a country accepted as a candidate for membership. We are only beginning to work out how we can effectively influence those that are not.

One thing is certain: there will be many players, and every one of them needs careful scrutiny. A European commission operation called (somewhat mysteriously) the European Instrument for Democracy and Human Rights has €1.1bn allocated for the seven years from 2007 to 2013. But are its slow, rule-bound, super-cautious bureaucratic procedures the best way to get the money to those who really make a difference on the ground in a country like Egypt or Pakistan? Past experience is not encouraging. The foundations of the German political parties are big players, with total budgets larger than the US's National Republican and National Democratic Institutes. The German party foundations did an inspirational job in countries like Spain and Chile 30 years ago, but have they become too bloated and complacent?

Each of the 27 member states does things differently. In Britain, for example, there's the Westminster Foundation for Democracy, but also stuff done directly by the Foreign Office and the Department for International Development. And then there's the new European Foundation for Democracy through Partnership, which aims to be a "knowledge hub" and ginger group, as well as giving small grants of its own. Far from the monolithic Brussels superstate of Eurosceptic nightmare, what we have here is more like herding cats.

The best we can hope for is a shared approach, not a single policy. But if we can achieve a shared approach, then our diversity will be a strength. Imagine that in a country such as Egypt or Morocco the myriad European players in democracy promotion would agree a set of priorities for that particular place and time, perhaps the judiciary and NGOs there. Then 100-plus European players go quietly to work in their different ways. Local anti-democratic rulers would hate it, of course, but in their agreements with the EU they have already signed up to the principles of respect for democracy, human rights and the rule of law. And what could they do about it? If they cut off three heads, there would still be 97 left. We need, in short, a benign European hydra for democracy: a modern version of an ancient Greek mythological monster to promote a modern version of ancient Greece's finest invention. Here's an idea whose time has come.

Timothygartonash.com