What nation was allowed to keep their government after World War 2?

Italy had overthrown Mussolini in 1943, and eventually joined the Allies (Italy even declared war on Japan in summer of 1945). Their new government was allowed to stay in power after the war- although in 1946, there was an election to abolish the kingdom, and Italy has been a republic ever since.

Japan's government was largely kept in place (mainly that the Emperor was allowed to stay in power) but the officials who had led the Japanese into the war were put on war crimes trials. Their laws were also rewritten to get rid of the conditions that led to their involvement in aggressive wars.

Otherwise, the rest of the Axis had their governments toppled. Also, most of the countries in Eastern Europe that were "liberated" by the Soviets had their governments replaced with Stalinist model communist dictatorships.