Whenever you can't do that -- which is always -- then "realism" amounts to "putting off uncontrollable events as long as possible" and "trying to get along with monsters." In other words, realism begins to overlap quite dangerously with appeasement. When you start to think, "Better the monster we know than the chaos we don't know," you are ready to go to Munich and return triumphantly with "peace in our time," which might, with luck, last as long as a year and a half.