1 and 3 are correct, this is due to the fact that modern technology is constantly growing and other developed nations are feeling threatened or inferior when another developed nation grows further ahead. National security has also grown global, just the threat of a foreign country developing nuclear capability is enough for another country to launch missle strikes or other acts in order to quell the threat of another nuclear capable country. 2 is not correct because industrial strategies are being shared throughout the world constantly and the safety of a country no longer stands by their standing army or navy, but by the threat of nuclear capability or a possibility of retaliation through explosive nature. Even today, most wars are done through the army holding down a line, and the navy/airforce launching long ranged missile attacks of various nature.
Probably because it would cause chaos in the area on what to do for a solution.
