What happens when the oil runs out?
That depends on whether the nation is prepared to operate without combustion engines. If the people have mostly switched over to electric vehicles, then operating an economy without oil isn't difficult. Sure, other forms of transportation still need oil, but the greatest consumption of oil is found in automobiles.

If the end of oil catches a nation unprepared, then things become quite chaotic. No oil means no more transportation and farming, and that's really all you need to know. No farming (or greatly diminished farming capacity) means no food. The United States, I submit, is about three meals away from mass social unrest. When the average American finds himself without food for three meals in a row, the ensuing chaos (riots, etc.) will make the United States a rather inhospitable place to be. Martial Law will immediately be declared, and the country will become a police state starvation camp. This can all be avoided, by the way, by shifting America away from an oil-based economy. If transportation is based on electricity rather than oil, none of these dire predictions need come true.

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"Never doubt that a small group of thoughtful and committed citizens can change the world. Indeed. Its the only thing that ever has." Margaret Mead