The DOJ/FBI still has to go back to the FISA court to have a warrant issued within a certain time frame.
I don't like the idea of warrentless wiretapping and the like. I personally don't see why it's necessary. It can be done without the names if the targets being made public.
And the issue with Flynn was not that he was being wiretapped but the Russian on the other end which is legal under FISA. Because of the nature of what was said on those calls Flynn's name was eventually unmasked.
The rest is history as his guilty plea indicates.
The republicans are barking up the wrong tree.
Simon Schama, the British historian, recently tweeted: “Indifference about the distinction between truth and lies is the precondition of fascism. When truth perishes so does freedom.”