The reliance could be seen on how we acquire our military draft.
For example, countries such as Russia and south Korea implemented a mandatory military services for all adult men. (they're require to served at the military for around 1-2 years).
United states on the other hand, does not implement such mandatory military draft. All of our forces were acquired through voluntary methods without government force.
Since the nature of war has changed, voluntary method is more than enough since war that conducted on modern time would most likely relied on mass destruction weapons or advanced vehicles.
This is because Abraham Lincoln's Gettysburg Address became very well known. The emancipation proclamation was saying that Lincoln would free the slaves. The last choice was also something Lincoln did that had a big impact because this is were the former slaves were going to be able to be free.
