A map showing the planned Brazil-to-Portugal undersea fiber-optic cable. (TeleGeography)

There's a new wrinkle in Brazil's plan to build a $185 million undersea fiber-optic cable that would connect it to Portugal and help the country avoid surveillance by U.S. intelligence authorities, reports Bloomberg: The cable will be built without the help of any U.S. companies.

While Brazil arguably led the world's outrage over the Edward Snowden disclosures, its ire has mellowed a bit in recent months. But that Brazilian authorities are still talking about a U.S.-free undersea link to Europe only underscores something that may be especially destructive to U.S. tech companies: Once you write foreign policy into fiber-optic cables, it stays that way for a long, long time.

To be sure, under President Dilma Rousseff, Brazil reacted strongly negatively, in ways big and little, to the Snowden disclosures in September 2013: Rousseff railed at the United Nations  about Brazil's commitment to "redouble its efforts to adopt legislation, technologies and mechanisms to protect us from the illegal interception of communications and data."

But more recently, she's been eager to work with the United States and U.S. partners to figure out ways to share governing responsibilities for the Internet.

"The phase of diplomatic retaliation seems to have passed," said Matt Taylor, an associate professor of political science and a Brazil specialist at American University.

But digital infrastructure the size of a 3,500-mile fiber-optic cables doesn't react as quickly as diplomacy. Brazilian officials decided at some point that the Fortaleza-to-Lisbon cable made both technological and political sense. And it will spend the next few years — the cable will be finished by 2016, they say — embodying that judgment in thousands of miles of undersea cable built and contracts that exclude U.S. firms.

That's not great news for the U.S. on the global technology stage, says Taylor: "These things are path dependent. When you decide that you're not going to work with U.S. companies, it can be hard to change things around mid-stream." Or mid-ocean, for that matter.