What percentage of a country's population could they field in a war and still function?

Answer 1

I think it would depend on the make-up of the country, industrial, agrarian, etc. and what economies they rely on. Also, what the demographics are - male/female ratios, median ages, etc. Also, do they rely on prison labor, percentage pacifists, religious make-up... so many factors, it would have to be a country by country basis.

Answer 2

I'll give you a clue....

Look at the country involved's unemployment figures.

On that basis, a major industrial nation could certainly manage at least 10 %, and in failing economies it could be higher than 30 %. Often war is just used as a way to keep one's own population from rebelling.

A little known fact of the Falklands ( Malvinas ) conflict of the arly 80's is that the British government was pretty close to giving away the real sovereignty just before the Argentine invasion, they were planning to hand over responsibility of the postal services to Buenos Aires. This might seem trivial, but not so, it's usually a good indicator of the political 'tide'.

Anyway, Galtieri and his boys in the 'Junta' had a major problem brewing fast, there was a junior officer ( Majors and below ) movement pressing for a take over of the 'Old Guard' Generals and Admirals etc. Galtieri pushed the invasion button largely to forestall this coup.

Everything is not always what it seems.

Answer 3

The above is correct, the worst I've heard of in modern times was the War of the Triple Alliance (1864-1870) where Paraguay declared war on all three of it's neighbors...Uruguay, Argentina, and Brazil. Over 90% of it's pre-war population was killed and it took decades to even begin to approach normalcy afterwards...link below.