With major economic interests at stake, the European Union must become a player in Southeast Asian security.

China's new assertiveness in its southern neighborhood has backfired. Smaller neighbors such as Vietnam and the Philippines are working hard to counterbalance what they perceive as a Chinese threat. Washington has reacted to the new tensions by making clear that it won't abandon its key security role in the region, recently announcing plans to shift 60 percent of its fleet to Asia (up from 50 percent). "Make no mistake, in a steady, deliberate and sustainable way, the United States military is rebalancing and bringing an enhanced capability development to this vital region," U.S. Secretary of Defense Leon Panetta said during a recent visit to the region.

China appears to be impressed by America's move towards strategic reassurance of its traditional allies and newer partners. Beijing has chosen not to show up at this year's Shangri-La Dialogue in Singapore, the most important annual meeting on Asian security, probably because of fear of being singled out for unfriendly behavior.

Europeans meanwhile—whose presence at the Shangri-La Dialogue was weak as usual—are not yet sure what to do about the new dynamic in the region.

European economic interests are in not only one, but several baskets. Although China, with its continually amazing growth rates, is a locomotive for German, and other companies, EU member states also maintain very important economic relations with China's southern neighbors. Association of Southeast Asian Nations(ASEAN) countries are the EU's third largest trading partner, after the United States and China. EU-ASEAN trade topped €200 billion last year—the EU is ASEAN's main export destination. In 2010, the EU invested €22 billion in ASEAN countries.

What Europeans hear when they travel in the region is an invitation for a more comprehensive partnership, not limited to trade. That should not be surprising. With a rising giant in the neighborhood, such as China, smaller neighbors naturally look for outside partners to they keep their sovereignty intact. Countries such as Vietnam and the Philippines, whose disputes with China over territorial claims in the South China Sea might become tense, need powerful friends wherever they can get them.

But the idea of any conflict with China makes European capitals nervous. Europeans have no inclination to get involved in territorial disputes in the South China Sea. They are worried that they might be pressed into taking sides against China. Europeans are usually quite happy to leave this kind of stuff to the Americans.

But can Brussels and other European capitals afford to stand by, ignoring the rising tensions and do business as usual? A major conflict between China and its neighbors would lead to a major disruption of the European economy, if not its break-down, as both regions are economically deeply interconnected. The EU needs to protect its investments in the region. It needs to make sure that the constant flow of manufactured goods from China, Thailand, Vietnam, and other countries is not interrupted. It wants to sell its own products to the region and it needs to keep the waterways that connect the two economic centers open and safe. If there is anything that the Europeans can do to minimize a threat to those interests, they have a clear obligation to act.

The EU is not a military player in the region, and it's safe to predict that it will not become one in the near future. But even without disposing of hard power, the EU can and should become a security player in Southeast Asia. As a vital economic partner, the EU has massive weight in the region. And Beijing knows very well that it can only keep delivering high growth rates—widely seen as the condition for the survival of the current regime—if its economic relations with Europe are in good shape. Putting this key economic relationship at risk would be suicidal for Chinese leaders.

The question for the EU is: are member states, especially the big ones, willing to put their combined weight behind a common political strategy towards the region? Do they see the longer-term benefits of an EU-wide coordinated approach or do they prefer the short-term gains of the bilateral approach?

If the EU gets its act together and wants to become a security actor in the region, it certainly has to work in close cooperation and coordination with the United States. America is and will remain the key outside player, with a strong inside presence. It has the military muscle and the political instruments to build and guarantee a security architecture in the region—if and as far as the regional players decide to cooperate. Given that the EU and the United States have very similar interests, there are good reasons to join forces with Washington.

But at the same time, it is important to raise the EU's political profile in the region. The more standing and leverage the EU has in the region, the more chances it has to work with regional partners and the United States on equal terms. More visits by European leaders to the region—and not only to China—would be a good start.

The main stumbling block for any security architecture in the region will be China's mistrust, and in this context Europe could play a key role. The challenge is to convince Beijing that these efforts are not about checking its power, but about building a framework that allows China to flourish and prosper.

Europe's message should consist of two key elements. First, we support America's efforts to build a security framework in the region, and we are ready to contribute what we can to such efforts. Second, developing such an architecture is not against China, but in China's vital interest. China needs friends. It is currently quite isolated, and this isolation is full of risks for everybody involved. To build a stable security architecture with institutions and mechanisms to solve conflicts—and to prevent that a mistake or a miscalculation might trigger a confrontation—is a key Chinese interest.

European history has demonstrated several times that without a stable, binding security framework in place, guaranteed by power, political passions can boil over and force political leaders into a logic that leads towards war—even if economic interdependence clearly points against such a course of events. European integration has helped, with NATO, to overcome such a dangerous configuration in Europe. Applying this lesson to its dealings with China and its neighbors would be a great contribution not only to world peace, but also to Europe's own prosperity.