Which country decided to practicipate in unrestricted warfare, even though other countries advised it not to?

well Germany: (who took over Austria, Poland, France ... who ran away ... and even Denmark, Slovakia, and hungry) did during ww2 and so did Italy: (basically took over most countries around it like: the swiss, Croatia and others) and japan: (who stormed into and took over china and got angry when the Europeans told japan to stop pillaging ... even though THEY themselves were, and took away and won a fight with Russia. which shocked everyone as Russia is strong as our country ... america)

The soviet union. (Now Russia)