Or, that in the future, will be in that position and must do so unhesitatingly.
There's no hint of that in the story, except that the writer will sometime soon write something that will get his grandkids on a death list. This doesn't put one in the position to nuke Iran, no matter how well one can argue the position for doing so. I'll state again that I think the message has to do with the story we all read - that's why the Time Traveler came back.