Central bankers are Delphic figures. They are supposed to be all-knowing, serious and solid, exuding confidence and authority. At the same time, however, they must maintain an air of unpredictability to keep markets from anticipating their moves. That is why last week's comments by Mr. Wim Duisenberg, head of the European Central Bank, were inexplicable. They violated that last rule, and by implication, undermined his claim to be serious, solid and credible. That is the last thing that the euro, Mr. Duisenberg or the ECB needs right now.

Since it was launched on Jan. 1, 1999, the euro has lost over 30 percent of its value. Once considered a challenger to the U.S. dollar's status as the world's leading reserve currency, the euro has instead spiraled steadily downward, leaving serious damage in its wake. Companies that bought euros have seen their investments devalued. Mazda Motors, for example, announced last week that exchange-rate fluctuations, primarily in the euro, had cost the company over $1 billion last year.

The lack of confidence in the currency has cast a shadow over the entire European project, as was made clear by Denmark's vote last month rejecting membership in the euro. Politicians worry that the ECB will have to boost interest rates to restore credibility in their currency; yet doing that would undermine the economic recovery that is now under way.