Yes, if the evidence is gathered illegally it will be tossed, particularly if there is, as you say, no other evidence.
However, what we’re looking at with what Mueller is running around doing is clearly hunting for MORE evidence. Even though the investigation was triggered by an illegally obtained warrant, this does not mean that any and all evidence it develops is ‘poisoned’ only that which stems directly from the warrant - which is most likely evidence against Carter Page.
The classic “Poisoned tree” case is Wong Sun V. United States (1963).
Narcotics agents recieved a tip from an unreliable informant that a man - Toy - was selling drugs. They then illegally entered his dry cleaners and Toy implicated a man named Jonny, who ultimately pointed the finger at Wong Sun as the drug supplier. The men were arraigned and released. Wong Sun later returned to the police station and gave a statement in which he confessed.
The Supreme Court ultimately decided that the testimony of Toy and Jonny, as well as the drugs found in the search of Wong Sun’s apartment were inadmissable: fruit of the poisoned tree. HOWEVER, Wong Sun’s confession was ruled admissable evidence. Simply because an investigation is begun poisoned it doesn’t mean the whole thing needs to be thrown out.
So in the case of Trump, Page, and Bobby Mule’s Flying Circus, evidence which stems directly from the FISA warrant and its intercepts would likely be ruled inadmissable, while testimony from someone like Pappadopoulous would most likely NOT be ruled the fruit of the poisoned tree, nor would evidence developed from subpoenaed financial documents, emails, or other communications.
In other words, Trump needs to shut this thing DOWN because people are definitely in actual legal jeopardy from the relentless digging Mueller is doing, we can’t count on the Supreme Court to just throw the thing out and I have no doubt that the AG of New York is all over this thing - limiting Trump’s ability to pardon.
which comes as a shock to exactly no one. The Mueller investigation is going to gather up some admissions, but of what? Nonexistent "collusion" whatever that means? The fact is he has done nothing so far and has had ample opportunity to prosecute the Manaford types for some thing relevant. Nobody is going to care about 13 Russian trolls and an admission or guilty plea for unrelated offenses done years ago.
I can’t believe you pulled out the “’63 Wong Sun” reference. But, seriously, you are correct. Excellent discussion, BTW.