Do you think Leiba Bronstein lost because of his?

Trotsky lost out to Stalin for a number of reasons:

Stalin organized his political support better,and thus outmaneuvered Trotsky politically.

Stalin was far more ruthless and ambitious than Trotsky.

Trotsky's plan of exporting the Bolshevik Revolution to the rest of Europe using the Red Army was likely to plunge Russia into a war against an international coalition that could only end in the overthrow of the Bolshevik regime in Russia - Trotsky's political support inside Russia,from senior Bolsheviks,was thus limited,as many of them recognized this.

Being Jewish had nothing to do with it - Communism is an avowedly atheist political ideology,so religion has no bearing.

Well we did let Jews lead us once (Lenin)...He did not do such a great job since all the Jews are still blaming Russians for Communism when they established it in the first place..