Ok, let's assume that the following scenario is actually possible, I would like to know how you feel when all these thing happen at the same time:
Bitcoin is under a 66% attack (double spends are happening)
Is also banned by the US, Russian, EU and China government by threat of 30 years jail time.
The real satoshi (proven by something) is found dead, killed.
The real question is how those came to be. From what we've seen pools getting 50% or more get severe community backlash - meaning that most of the miners switch pools to reduce the size of that pool. The second option is a possibility minus the jail time (how is it illegal to accept something else as a form of payment - it's just the barter system). I'm not even going to bother with the last.
Now to answer your hypothetical - if all three happened, I'd probably just hold on to what I have and see where it goes (not much value in divesting in something that will have already hit rock bottom thanks to those factors). Bitcoins are an experiment, I'm keeping some in case - but if they become worthless overnight I won't be too greatly affected.