- The indicted Russians will never stand trial. That's the easy one.
- The Russians will retaliate. They will either (a) indict 12 random U.S. military officials; (b) kick 12 random Americans out of Russia, accusing them of espionage; and/or (c) arrest 12 Americans for espionage. It could be all three, actually.
As an aside, I would not be surprised if an attorney shows up in a U.S. court, as happened with Mueller's previous indictments, purporting to represent the indicted Russians, and then asks for discovery and a speedy trial. And Mueller will have to delay and obfuscate yet again.