Washington hastily pledged that the German chancellor, Angela Merkel, leader of Europe’s most powerful economy, was not the target of current surveillance and would not be in the future, while conspicuously saying nothing about the past. After a similar furor with France, the call was the second time in 48 hours that the president found himself on the phone with a close European ally to argue that the unceasing revelations of invasive American intelligence gathering should not undermine decades of hard-won trans-Atlantic trust.
Both episodes illustrated the diplomatic challenge to the United States posed by the cache of documents that Mr. Snowden handed to the journalist Glenn Greenwald. Last week, Mr. Greenwald concluded a deal with the eBay founder Pierre Omidyar to build a new media platform that aims in part to publicize other revelations from the data Mr. Greenwald now possesses.
The damage to core American relationships continues to mount. Last month, President Dilma Rousseff of Brazil postponed a state visit to the United States after Brazilian news media reports — fed by material from Mr. Greenwald — that the N.S.A. had intercepted messages from Ms. Rousseff, her aides and the state oil company, Petrobras. Recently, the German newsmagazine Der Spiegel, which has said it has a stack of Snowden documents, suggested that United States intelligence had gained access to communications to and from President Felipe Calderón of Mexico when he was still in office.
