Better examples would be Germany and Japan. These were two countries with no real democratic heritage at the time we conquered them in 1945. (In Japan's case, it had been in the Middle Ages until 1854). Lots of people thought neither of those countries could develop free, democratic systems either; one swift boot to ass from the USA cured that nonsense.Of course no popular elections throughout the 1920s or even in 1933 in Germany was there? Germany and Japan both had working, albeit limited, democracies before WWII. And look what it brought the Germans. Yes, rah-rah, democracy..
Germany between the wars had a badly-flawed Constitution, an Army that was independent of the state, and a bitter legacy of resentment from the Versailles Treaty. In addition, the United States completely disengaged from the process of rebuilding Germany. We did not repeat that mistake in 1945 -- making the case that involvement by our country worked.
Had we remained engaged after WWI, we would likely have avoid the holocaust of WWII.
And as far as "democracy" in Japan before WWII -- you've got to be kidding. The Army ran the country, not the civilian government. That was a legacy of the "Shogun" era in Japan -- the country modernized, but the Army still called the shots. Only the victory of the United States changed that.