Little Hawk commented:

That was the situation in the USA in the 50's and 60's and during the Vietnam War.

In the US, that IS THE SITUATION NOW. (with reference to LH's description of the situation)

Selective Service

It is still a requirement that all our young men (I'm not sure about the others) are required to register so that their availability to be drafted can be determined. [Enforcement of the requirement may(?) be less rigorous than when some still were being called up(?).]

Although it's been several decades since I've been asked for it, I still carry my "draft card" in my wallet, "just in case," since technically I'm required to do so, but mostly because it states that I did my time and cannot be recalled even by act of Congress.

[The card is of course very faint and tenuous assurance ..., and my ancient and venerable age is likely a better protection against being drafted. Feebleness of mind and body may also help.]

Just to be clear on the issue.

John