It should be noted that the party that he joined was the Labour Party, which he very successfully moulded to take the form of his particular ideology.
National Socialism was therefore the anti-thesis of International Marxism because National Socialists wanted socialism for their own country, but rejected World Communism, which was a feature of International Marxism.
Trotsky clung to Marx's purist goal of World Communism until Stalin decisively saw to it that the Russians concentrated only on Russia Empire. Mao was only interested in the Socialism for China and not any other peoples who did not come under the rule of China.
It could therefore be said that any form of Socialism that had no international ambitions is in fact National Socialism.
The Russians can be said to have given up on their National Socialism the moment Gorbachev abandoned their one-party system - which is the distinguishing feature of National Socialism.
It can therefore be said that the Chinese remain the only living flourishing practitioners of National Socialism (with Chinese characteristics), which is a very interesting thought indeed.
National Socialism appears to have served the Chinese rather well. They have certainly made a point of not being obviously aggressive and expansionist. "One country two systems" demonstrates that they are capable of compromising when the need arises. Since China is undoubtedly an empire, they are very keen emphasising racial harmony, very understandably.
What a shame Hitler is not alive today. It would be delicious to be able to put the point to him on The Today Programme, perhaps, that his National Socialism is perhaps being implemented better by the Chinese than by the Germans, and whether he still stands by all the nonsense that was his racial theory.
He did after all say:
"Believe me, National Socialism would not be worth anything if it were to be confined to Germany and did not secure the rule of the superior race over the whole world for at least one or two thousand years."
It would be delicious to be able to call the Singaporeans Nazis too, but it appears they only have a de facto one-party state, not a de jure one. Shame.