* Crack ECDSA and forge transactions (slowly/slyly enough to make a hard fork fix infeasible) * Create exchange(s), get users, then implode them ("oops, bad co

* Crack ECDSA and forge transactions (slowly/slyly enough to make a hard fork fix infeasible) * Create exchange(s), get users, then implode them ("oops, bad code / we got hacked") (bonus: free $ for black ops) * Create competing coins, either crappy ones just to suck away mindshare or legit one(s) backed by the gov't that grants some stability through gov't capability. Or heck just designed well enough that people want to actually use it for spending. Or just go the more traditional / direct route and create regulations or make it outright illegal, and shut down exchanges and throw people in jail (probably the most effective)