US legally spies on foreign persons in foreign countries. Foreign governments spy on US citizens. US has mutual agreements with other counties to trade data.
This leads to entrapment (Flynn), and parallel construction. All ways to get around 4th amendment.
The FISA warrants to spy on the official target Page can get several layers of other contacts. Rice, Powers et al unmasked US citizens to gather more data instead of keeping US citizen ID secret as they were supposed to.
And isn't this the biggest point?
Either the Constitution is the supreme law of the land, or it is not. Period.