In history, besides america, Asia and Europe would be in danger in the world wars due to the Axis trying to control. If it weren't for the Allies, half the world would be under the hands of Hitler, Mussolini, and The imperial army. This is the past, but actions have back then have changed the future for the people living through that specific time period. It has changed the present because now Asia and Europe do not have to worry about being invaded. As stated before, one action can lead to another. For example, whenever Japan invaded Malaysia. Malaysia was once a british colony, the british fled because of the imperial army leaving Malaysia to be conquered by Japan. This lead to deaths, and also led to the independence of Malaysia after the world war due to the anger of being betrayed by the English. Truth is, the Axis could not have what they wanted and this puts us in present which means half the world is not conquered.
Historically, Germany's economy was pretty low back then, a theory used to improve economy is to start a war. That is what Hitler tried doing and it failed horribly. Bush tried doing the same by going over to Iraq hoping it will boost American economy and that didn't work. And same with Obama, he is planning to travel to Iraq to fight ISIS as an excuse hoping to raise the economy for America. This is the present and no one knows it will work. But based on the past, it has failed horribly. Honestly, the truth is is that this theory will not be proven to work even till this day.
This chain reactive theory has been going on ever since the world wars, and maybe even before that. Not everything works out and we cannot have everything we want and this is what it tells us now. In conclusion, the past, present, and the future are all inter connected with what we do. One mistake can lead to another, or one good decision can lead to another. However you perceive it as, the moral is is that everything can lead to another whether good or bad. Life is a chain reaction and it can lead to a bad truth or a good one.