Why did Italy leave the league of nations?

Italy left the left the league after the Abyssinian crisis. Mussolini (current Italian ruler) wanted to restore the "glory days of the Roman Empire", i believe the main reason Italy left the league was that Italy knew the league could not work because the economic sanctions did not work because the USA was not part of the league and the USA not being a part of the league sped up the failure of the league of nations.