Once you are outside of the USA, anything that you say can be eavesdropped on without a court order by US authorities... and authorities from every other country. This rarely-mentioned exception in the US eavesdropping law was recently reaffirmed in this terrorist bombing case.
"El-Hage contends that the District Court erred by (1) recognizing a foreign intelligence
exception to the Fourth Amendment’s warrant requirement, (2) concluding that the search of El-Hage’s home and surveillance of his telephone lines qualified for inclusion in that exception, and (3) resolving El-Hage’s motion on the basis of an ex parte review of classified materials, without affording El-Hage’s counsel access to those materials or holding a suppression hearing. Because we hold that the Fourth Amendment’s requirement of reasonableness—and not the Warrant Clause—governs extraterritorial searches of U.S. citizens and that the searches challenged on this appeal were reasonable, we find no error in the District Court’s denial of El-Hage’s suppression motion."
