One potential nuclear deterrent is the threat of a Proof-of-Work change. While the effects would be disruptive, it would effectively negate any bullying potential. I hope it doesn't come to that, but when you have Bitcoin Unlimited tantrums with people saying they'll sue others - it pretty much tells you what you need to know.
Which is why we must do it, and "now" (i.e. as soon as a testing and roll-out schedule could permit)
The miners are fairly transparently uninterested in the value of their R&D/manufacturing/facility investment, otherwise they would not be doing this. The fact that Bitmain have spent several years developing everything they have, only in order to be as obstructive/destructive as possible should demonstrate that.
Get a grip, everyone. They're not playing nice, throwing away millions in investment just to screw up the entire value proposition of Bitcoin is proof positive of that.
PoW fork, "now". "Nuke the site from orbit, it's the only way to be sure"