Going on yesterday's media coverage, the leaders of the two nations are united in the aftermath of this tragedy. But, with the Russians apparently calling the shots in the investigation (correct me if I'm wrong on that), I wonder how much longer this harmony will exist. Would the Polish public accept an early finding that the flight crew were entirely to blame, a finding that seems already to have been pre-empted by the statements of Russian officials?
A backlash in Poland is a strong possibility. That is why consideration should have been given to calling in a third-party investigation team as early as possible, preferably even before Russians (or Poles) started sifting the wreckage, and retrieving the recorders. Of course, the latter sounds a utopian concept in the real world. Sad to say that today, the third day, it is almost certainly too late.
Predicting the response to an investigation before the investigation has been completed is speculative and serves no purpose.
The investigators will call for outside help if and when they need it and certainly have no need for purely political observations. I'm quite sure that Putin is not calling the shots, but only monitoring what gets released.
If there is any controversy in the findings then look for this among the investigators and not what's made up by outside speculations.
As always in an air accident investigation, blame is not the objective although it may be manufactured in the minds of the public.