Reposting a (cut-down and edited) JoeySteel diatribe on this (with parts highlighted by me):
"do ya'll think the USSR would have been better off under Trotsky?"
No but this is a fun question. It is a question I have asked before when I did not know enough about the Communist movement and the Soviet Unions history. If you asked me today for instance I would say there is little I (or anyone hypothetical) would’ve done differently given the material circumstances at the time. And this leads back to liberal Great Man Theory. On this topic Plekhanov wrote a masterpiece to expound that history is not formed by individuals - the masses push forward their leaders (the individuals) and in their leaders they express their agency.
If, owing to certain mechanical or physiological causes unconnected with the general course of the social-political and intellectual development of Italy, Raphael, Michelangelo and Leonardo da Vinci had died in their infancy, Italian art would have been less perfect, but the general trend of its development in the period of the Renaissance would have remained the same. Raphael, Leonardo da Vinci and Michelangelo did not create this trend; they were merely its best representatives. True, usually a whole school springs up around a man of genius, and his pupils try to copy his methods to the minutest details; that is why the gap that would have been left in Italian art in the period of the Renaissance by the early death of Raphael, Michelangelo and Leonardo da Vinci would have strongly influenced many of the secondary features of its subsequent history. But in essence, there would have been no change in this history, provided there were no important change in the general course of the intellectual development of Italy due to general causes
–Plekhanov, On the Role of the Individual in History
I think Marxists that wonder about “this or that leader” should study this piece as it really expounds the Marxist view of the individual in history. With the role of the individual placed in its proper context let’s go down this rabbit hole. First we should ask why so many budding Marxists ask this question(as I myself did)
... [a bunch of stuff here about Trotsky and the Hearst Press] ...
So now onto whether Trotsky would’ve made a better leader. In order to do this he would’ve had to become leader of the Bolshevik party so let’s see if this is possible.
... [some historical context about Trotsky pre-revolution] ...
In 1927 the bloc of Trotskyites and Zinovievites were to put their platform of the opposition to the Bolshevik party at the 15th party congress. 724,000 members voted for the Central Committee and 4000 voted for Trotskys Opposition.
At the Fifteenth Party Conference, Trotsky and Zinoviev finally destroyed themselves politically. Trotsky made a lengthy speech and had to ask repeatedly for more time. He was interrupted constantly by ridicule and laughter. Zinoviev grovelled and begged forgiveness for his errors. He, too, was heckled and ridiculed. Both had been arrogant in power and now they were humiliated and defeated. It was left to Bukharin to make the final savage attack on them; the delegates, thirsting for blood, applauded loudly.
The main discussion at the conference was not on the opposition, but on Stalin's new theory of "socialism in one country." It bore the stamp of his mind and outlook, and it marked the beginning of the Stalinist era. The Russian revolutionary drive had been losing momentum since the end of the Civil War and the process had accelerated after Lenin's death. A new policy was needed that would inspire the Russian people to undertake the superhuman task of carrying their country on from the October Revolution towards socialism and communism. That policy was "socialism in one country." Its emotional appeal was overwhelming. It aroused a new fervor in the party, and pride in the revolution spread beyond the party ranks. It was a declaration of independence from the West and of faith in the capacity of their country to forge ahead, creating its own future alone and unsupported. Backward Russia, for so long treated as lagging on the outskirts of Western civilization, would show herself to be advanced and at the center of civilization in the coming millennium.
–Ian Grey, Stalin p.215
So we see Socialism in One Country as a foreign policy that drove a new fervour in the party and reinstilled the revolutionary drive in the Communist Party. Had Permanent Revolution and its eurocentric view won out I guess we can envisage the collapsing and disintegration of the Party starting in 1927. In November Trotsky was to present a statement to the Central Committee demanding it be printed and sent to members which was rejected. Trotsky had set up his own secret printing press which the OGPU found. He then setup his own opposition demonstration during the October celebrations which was a grave breach of Lenins non-factionalism and party rules and was promptly expelled from the party.
Conclusion - So we've basically got to the point where Trotskys ideas are discredited in the party where the CC can garner 724,000 votes for its program and Trotskys opposition can only get 4000 votes. So the only thing we can do here is "magic" Trotsky to becoming leader and instead of the Bolshevik party being full of Marxist-Leninists being full of Trotskyites (otherwise they'd have chosen a different leader to Trotsky). So if he's leader of the Bolsheviks I don't see him executing a successful revolution under his leadership. He was unable to unify one of the many parties he was in or led during that period as actual history so why would it be any different if he was leader of the bolsheviks at any point? We saw Lenin characterise him as having "no ideological definiteness" and merely "flitting from one group to the next with high sounding and pompous phrases". But lets magic him into producing a successful revolution.
So lets see they go all in on Permanent Revolution - with the collapse of all the revolutions across Europe which are stamped out by reaction in the early 1920s (Finland/Hungary/Germany/Romania etc. etc.) you would likely see a demoralised Communist Party due to the Trotskyite eurocentric belief no socialism can survive on its own and they were dependent on revolution breaking out in the West. At this point it means either the Communist Party dies a slow death starting in 1927 due to this demoralisation or we go on Trotskyite adventurism and Trotsky decides to use the Red Army to invade neighbouring countries. This was tried in 1920 and the Red Army suffered a resounding defeat in Poland which resulted in Poland annexing parts of Ukraine/Belarus and Lithuania from the Soviet Union. Given the state of the USSR in 1927 (only just recovering from World war, civil war then the 1921 famine). So Trotsky is successful in uniting the disparate Capitalist forces in 1927 instead of Stalins Socialism in One Country which is a masterplay at foreign policy. Don't believe me though I'll let Stephen Kotkin explain why it's a masterpiece [this was a streamable.com link but it's gone now]
If somehow Trotsky makes it to 1936 the USSR would be full of terror and paralysed defeatism due to Trotskys defeatism in his Revolution Betrayed where he states that
Can we, however, expect that the Soviet Union will come out of the coming great war without defeat? To this frankly posed question, we will answer as frankly: If the war should remain only a war, the defeat of the Soviet Union would be inevitable. In a technical, economic, and military sense, imperialism in incomparably more strong. If it is not paralyzed by revolution in the West, imperialism will sweep away the regime which issued from the October revolution.
–Trotsky, Revolution Betrayed, 1936
Compare this to Stalins speech of 1941
The enemy is not so strong as some frightened little intellectuals picture him. The devil is not so terrible as he is painted. Who can deny that our Red Army has more than once put the vaunted German troops to panic flight? If one judges, not by the boastful assertions of the German propagandists, but by the actual position of Germany, it will not be difficult to understand that the German-fascist invaders are facing disaster. Hunger and impoverishment reign in Germany to-day; in four months of war Germany has lost four and a half million men; Germany is bleeding, her reserves of man-power are giving out, the spirit of indignation is spreading not only among the peoples of Europe who have fallen under the yoke of the German invaders but also among the German people themselves, who see no end to war. The German invaders are straining their last efforts. There is no doubt that Germany cannot sustain such a strain for long. Another few months, another half-year, perhaps another year, and Hitlerite Germany must burst under the pressure of her crimes.
–Stalin, Speech at the Red Army Paradeon the Red Square, Moscow
continued