And that's before you even consider the willingness of US courts to prosecute foreign nationals for breaking US laws on foreign territory, where one or more US citizens may have been tangentially affected by it.
Law enforcement cannot be above the law. It destroys the principles that make laws worth having and enforcing.
Congress is capable of enacting laws with extraterritorial reach. I am unaware of any law that should be interpreted to criminalize the NSA's international spying.
then there Article 2 Section 8 which does not grate the authority to create and agency such as the NSA or preform international Spying thus since the constitution does not expressly grant such authority the Federal Government is barred from such activity
They just have a problem applying the law to the government when the actions are over seas..
Nice little loop hole they carved out for themselves...