If you are seriously worried about #3 then you should sell every share of every stock you have. Also take your money out of the bank and keep it under your mattress. And for good measure sell your house and move to the woods. Sorry, I don't mean to patronize you too much, but if you are going to invest with that scenario in mind, then there is no point because you would sell everything and buy nothing. If something like that happens, there is no way to prepare, except keeping your money under your mattress. If you do not want to do that then there is no point worrying about it. It is sort of like worrying about getting run over by a bus or hit by lightning. If it happens you are screwed, but if you worry about it you will ruin your life. And then if it doesn't happen the good life that you have will be markedly worse as you spent all of you time and energy worrying as opposed to planning (or investing).
I think that it is a realistic possibility. Ask yourself if anyone predicted in 1986 that the Soviet Union would not exist 4-years later. It happened really fast as people lost confidence in that government / economy. How is the US any different? In many ways, the US is exposed to riots and civil war as its people are not prepared for serious hardship.
However, selling "everything" and holding on to cash (dollars) would be really foolish if you thought that there is a 25% chance of the US falling apart as a nation. It would make sense to own gold/silver and investments into resources (food/water/energy). My question was: does it actually make sense to continue holding FRO as it is a critical part of the energy distribution chain?