Of course Congress has the power to impeach for high crimes and misdemeanors. This has nothing to do with what we are talking about. Congress cannot micromanage explicit executive powers in the Constitution. This isn't speculation. It is the history of our Republic, and the way the Constitution has operated from day one.
I want to know the Constitutional clause which suggests that the courts have the authority to authorize a warrant to bug a phone in Germany (or otherwise monitor foreign communications). If they don't...then who do people think does? Pretty clearly that falls within the context of foreign policy, military or diplomatic.
Exactly!