<I am more and more inclined to the view that Trump's ultimate fear re Russia is the exposition of some sort of Putin financial stranglehold on Trump.>
I think that's EXACTLY right.  Of course, Trump doesn't want to be impeached, convicted and removed from office; but I think that concerns him less -- far less -- than the possibility that his criminal empire will unravel as Mueller begins tugging at the threads of his tax and finance records.