The unstated message is that the NSA only spies on Americans in such extreme circumstances rather than the truth, which is they spy on virtually all electronic communications in the entire world via Echelon and Carnivore systems. They can easily do this legally via their partnerships with the Aussies and Brits who are technical partners in the Echelon spy system.
And what about the rumour of a trapdoor in Echelon that lets you spy on US. So far we have fought alongside the U.S. in two World Wars, Korea, Vietnam, Somalia, Afghanistan and now, Iraq.
Thanks to financial and documentary assistance, your CIA brought down one of our most popular governments, helped set up a merchant bank to wash dirty money and 'disappeared' one of the principals, an ex-CIA agent, when the bank collapsed, and jailed a communications specialist when he blew the whistle of the cutting of Australia out of the intelligence loop. Even your intel bases in Australia seem to be sparing with sharing their information. Still, we remain friends so I guess we must be a patient people.