with Trotsky in power there would be no nazy germany as he would try his best to inforce the ideas of the internacionala and support actively any and all comunist or socialist parties in europe and azia, as best as soviet economy could manage affcourse
this means the german socialists would get arms, truckloads of them, the warious post war revolutions in east europe would be mostly sucesfull, the italian left would be told or even ordered to stand up to fashists, and the spanish civil war would probbably not end as it did, wath with italy and germany in civil war themselwes
comunist parties around the world would be more numerous more autonomus and much more efficient
in the end even if the whole of europe would not necessarily become comunist the distribution and nature of comunism and socialism in the world would be much different
(all these things staljin did not do as he considered the internacionala to be a waste of time, without real geostartegic or political importance for him personaly as well as the soviet empire, and demanded total obedience of comunist parties in other countries, basically making them visarionović fan clubs incapable of real action
he denied help to the german comunists in the 20is, and for various relatively apsurd reasons limited the help he sent republican spain to political comesars that took care that ewerithing is done PC acording to staljinist worldwiew, ewen to the poin of shooting people on theyr own side, and seweral boatloads of old weapons, just to show he cares)
on the other hand all this would cause largescale mobilisation of the worldwide reaction, and there would probbably be france and england arming franco and mussolini and cracking down heavily on its own socialists movements, with a domino effect theory developing long before 1950, and the red terror scare causing wars all ower the world possibly even the cause of WWII
and this all belongs to the post 1900 forum