What hashrate would Bitcoin require to sit safely above the potential interference of (state-level) bad actors? Have there been analyses/estimates on this subject? I understand miners have more incentive to be honest than to undermine the network they maintain, but what if, finances aside, some entity with no stake in Bitcoin decides to redirect a couple of datacentres to the BTC network with the intention to wreak havoc. What kind of influence would this have on the network?