Secret Services tend to grab more an more power because they are difficult to control. They tend to work outside the checks and balances of modern democracies.
Now the NSA has bugged EU offices
http://www.cbsnews.com/8301-202_162-57591678/european-officials-lash-out-at-new-nsa-spying-report/
I'm curious to hear the official reasons. What is it now? Terrorism again?

Because...they could? America used ULTRA to basically read their allies' mail, which is why ULTRA wasn't declassified until the 1970s.

At the moment it's a pure skandal. PRISM is a violation of international law and diplomatic conventions. As I wrote above, it's not about terrorism. It's political and industrial espionage.

The European governments shy away from protesting, obviously because they don't want to endanger the free trade agreement.
Morales' airplane is denied transit rights by France, Spain and Portugal because of (false) allegations he had hidden Snowden in the plane. The airplane of a president enjoys immunity. So even if he had hidden Snowden, it would have been a violation of international conventions. But who gave the orders of this illegal denial? I can't imagine Hollande to give that order voluntarily. Im sure: They obeyed to requests from the US administration.
Do the US manoeuvre themselves completely outside international law?
That's the end of rule of law.