The China-European Union (EU) summit in Nanjing on Monday was the last such meeting under the rotating EU presidency (in this case Sweden). The very next day the Lisbon Treaty came into force.

Many diplomats and analysts are now asking whether it will change the way the EU conducts its business. Will the EU really become more coherent and visible in its foreign policy? What will be the impact of the appointments of two top EU leaders? Why were Herman Van Rompuy and Catherine Ashton chosen, especially when there were more prominent personalities like Tony Blair on offer?

Van Rompuy was chosen European Council president because the heads of state and government wanted a low-key figure from the majority, center-right political grouping. They were not looking for a "president of Europe" but a chairman to provide some continuity between the quarterly meetings of the European Council (the group of heads of state and government).

Ashton was chosen high representative for EU's foreign affairs and security policy because the center-left had a strong claim for one of the top three EU jobs - and because she is a woman. The center-right had Jose Manuel Barroso and Jerzy Busek as presidents of the European Commission and the European Parliament. They had Anders Fogh Rasmussen, too, as secretary general of NATO. On top of the socialist wish list was the UK's David Milliband but he declined the offer, preferring to stay in British politics.

Ashton will have a far heavier workload and travel schedule than Van Rompuy. Apart from amassing millions of "frequent-flyer" points in the next five years, she will also have to chair EU foreign ministers' meetings, take part in summits, political dialogue meetings and speak for the EU at international conferences. In addition she will be a vice-president of the European Commission, shoulder the responsibility for the new external action service (EU diplomatic service), have a staff of thousands of people and a budget of billions of euros to be spent overseas. All this makes one thing sure: She will not get much sleep in the coming months.

Barroso is perhaps the biggest winner in the Lisbon appointments. He is much better known than Van Rompuy or Ashton who is essentially one of his employees. At future summits it is likely that Barroso will be primus inter pares.

The European Commission, too, has been strengthened through these appointments. Ashton has been a commission member for more than a year and understands its internal workings, and hence is likely to pay more attention to its positions and interests in the setting-up of the external action service. The commission's bureaucracy will be well placed to provide her with the necessary background and briefing papers that she will inevitably need. Under the Lisbon Treaty, the high representative will have the right of initiative in foreign policy.

The new arrangements should provide more coherence, continuity and visibility for the EU foreign policy, but only if the member states agree on major policy issues. Since the disastrous split over Iraq in 2003, the EU has improved its ability to speak with one voice on issues ranging from Afghanistan and Iran to trade and climate change. The bottom line for all foreign ministers is that they know they are more likely to achieve their national interests by working through the 500-million strong EU than by trying to act on their own. But questions of prestige and vanity often interfere with logic.

How will the changes affect EU-China relations? The answer is not much, because all 27 EU member states have to agree on policy. This means no change in the near future on lifting the arms embargo or granting China the status of a market economy. Beijing will still have to deal with a number of interlocutors in Brussels and the capitals of EU countries. There will be no single telephone number. But the transformation of the European Commission delegation in Beijing (and other capitals) into a EU mission will, in time, also have an impact on diplomatic relations. The EU ambassador will increasingly speak on behalf of the 27 member states.

One other change that could have an impact on China is the increased role of the European Parliament, which now has the right to approve all agreements with third countries. The parliament's position has been complicated by the large number of smaller parties and independents that won seats in last year's elections. Hence, China and other countries would be well advised to pay more attention to the parliament.

The Lisbon Treaty marks an important step forward for the EU. It is the fifth treaty in 22 years and, given the struggle to get it ratified, likely to be the last for at least the next decade. It is another sign of how the EU progresses gradually - not through great leaps forward but by shuffling forward in an ungainly convoy. It may not be easy to understand, but it reflects the current level of ambition of the member states. Its impact, therefore, will be felt gradually by China and other strategic partners of the EU.

The author is adjunct professor at the Hertie School of Governance, Berlin. He is a former adviser to the European Commission and director of the EU-China academic network.