ruining a country; national ruin
Refers to the act or process of destroying a nation, often through misrule, war, or moral decay.
Reckless fiscal policy leads to the ruin of a nation.
Historians called that policy the road to national ruin.
ruined country; fallen nation
Describes a country that has already been destroyed or has ceased to exist as a political entity.
That novel is the story of a prince of a ruined country.
立国 refers to the founding or establishment of a nation, whereas 亡国 refers to a nation's fall or ruin.
亡国 refers to the ruin or downfall of a nation, the opposite of 救国, which means saving the nation from such a fate.
Compound of 亡 (ぼう, 'to perish, to be ruined') and 国 (こく, 'country'). The kanji combination directly conveys the meaning of a country's ruin or a ruined country.