In XX century Poland declared war only once. On which country?
Poland declared war on Japan on 20th December 194 as most of WW2 allies. Though Empire of Japan refused to accept a state of war due to friendly relations between the two countries. Despite that legally the state of war lasted until 8th February 1957. It might be the longest war without any clash.
reach: rather country specific20th centuryhistory of PolandPolandwars
Illustration: Kelly Short