I haven't seen any evidence of programs that are prima facie unconstitutional. You may wish that the Fourth Amendment required a warrant to search any of your communications, but that's not how the courts have interpreted it. Nations have been opening messages that crossed their borders for centuries.

That's not to say each and every instance of these programs has always been scrupulously constitutional, but we never expect our government to get it right 100% of the time. That's why the FISA court exists. You may wish its oversight were stronger or its opinions always public, but again, nothing about how it operates is obviously unconstitutional. Certainly not as self-evidently as some people around here seem to assume.

If America's founders had wanted the government to conduct secret tribunals, they would have made provision for such in the Constitution.

Instead, their intentions clearly were in the other direction.

They are opening messages that don't cross borders.

Deliberately? Which program does that?