If all countries except for Australia, Canada, NZ, U.S., and most EU countries disappeared from Earth, would there ever be any international war again?

Theoretical situation: All countries except for some (list below), along with their territories and people, disappear from Earth. Will there ever be any international war again? The countries that stay on Earth are: Australia, Austria, Belgium, Canada, Croatia, Czech Republic, Denmark, Estonia, Finland, France, Germany, Hungary, Iceland, Ireland, Italy, Latvia, Liechtenstein, Lithuania, Luxembourg, Malta, Netherlands, New Zealand, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland, the United Kingdom, and the United States (only countries with the "very high human development" status are in the list).