Prosecute Don Jr for what? Even on CNN tonight, Jeffrey Toobin and Jonathan Turley both said that no crime was committed. None whatsoever. Alan Dershowitz on Twitter said the same.
The basis for prosecution won’t be meeting with the Russian gal. How they will get him is a perjury trap like they did Scooter Libby. The goal is to indict him for anything...this meeting is just a pretext for Mueller to build a trap in his investigation.