On December 16, 2005, The New York Times reported that the Bush administration was spying on American citizens without a warrant.
Unintentionally: Deliberately (albeit perhaps inadequately) avoiding purely domestic intercepts and destroying them when found. Subsequent legislation has attempted to make such intercepts even less likely and more transient.
That's a pretty important qualification. Why didn't you mention it? Your phrasing could equally apply to a program targeted at phone calls between California and New York.