The temporary after-effects of a tragedy big enough to attract public attention, whereby politicians talk on and on (and on and on...) about how people need to be more civil and respectful of each other, when everyone knows the new mindset is a temporary one.
Can also be used to describe what happens after a business aquisition when the CEO of the expanded company addresses the employees of the acquired firm and says 'we're all one big family', just before the layoff notices are sent.
Person 1: I think that due to (fill in tragedy here) people are going to think before they do or say something hurtful when they disagree.
Person 2: Why, because of all that kum ba yada yada yada on TV? Don't hold your breath.