Many thanks to Daniel for his fraternal comments, which I have only just seen. I apologise for my misspelling of Jogiches, an inexcusable piece of sloppiness. But on the other points I stand by my arguments.
1) “criticizes Levi over irrelevant personal subjects”. Not irrelevant. I was establishing that Levi didn’t have the personal and psychological qualities required in a good leader. There are many in the movement who have great talents but who do not have the leadership qualities which Lenin, for example, possessed in abundance.
2) My account of Levi’s “consistent failure to deal with … ultra-leftism” is described as “absurd”. Levi “dealt with” the ultra-lefts by expelling them. My argument is that it would have been better to try to persuade them and win over at least a section. Not easy, but nobody said revolutionary leadership was easy.
3) “Zinoviev and Béla Kun, the organizers of the “March Action” putsch in 1921”. The March Action was a total disaster – it was NOT a “putsch. It had the support of around 200,000 workers. While the Comintern leadership was certainly not innocent, the March Action also had roots in native German ultraleftism.
4) “Zinoviev and Béla Kun … should have been defenestrated at the Comintern’s third congress, not Levi.” For those of us whose experience has been in the small groupings of the far left it may seem that a split is the best way to deal with a disagreement. After all, the left has seen enough splits. Lenin was in a quite different situation. A major split in the Comintern and/or the KPD would have been a disaster at a time when the possibility of spreading the revolution in the next couple of years hung in the balance. Lenin’s efforts during the congress, as reported by Zetkin, were for trying to hold the movement together. The “defenestration” of Zinoviev would certainly have provoked a crisis. And Lenin did not defenestrate Levi – on the contrary, he proposed a formula whereby Levi could return to the CI and KPD – which Levi, in his arrogance, refused.

Paul Levi, Brief an Lenin (27 März 1919)
https://goo.gl/TIZUPx

Paul Levi, Leitsätze über kommunistische Grundsätze und Taktik –
Heidelberg Parteitag der KPD (20-24 Oktober 1919)
http://tinyurl.com/lcrgch5

Paul Levi, Die politische Lage und die K.P.D. Rede auf dem
Oktober-Parteitag der K.P.D. nebst den vom Parteitag angenommenen
Leitsätzen. Hrsg. von der Kommunistischen Partei Deutschlands, 1919.
http://tinyurl.com/m37rgv4

Paul Levi, “Brief an das Zentralkomitee der Kommunistischen Partei
Deutschlands” (16 März 1920), Die Kommunistische Internationale, 2.
Jg. 1920, Nr. 12, pp. 147-150.
http://tinyurl.com/m9pzwjh

Paul Levi, “Erklärung der Zentrale der KPD vom 23. März 1920 (‘loyale
Opposition’)”, in Spartakus, “Der Kapp-Lüttwitz-Putsch (Brief aus
Deutschland) (Berlin, April 1920),” Die Kommunistische Internationale,
2. Jg., 1920, Nr. 10, pp. 161.
http://tinyurl.com/llwenvx

Paul Levi, Die Weltlage und die deutsche Revolution. Rede, gehalten
auf dem 4. Parteitag der KPD (Spartakusbund) in Berlin am 14. April
1920. Hrsg. von der Kommunistischen Partei Deutschlands, 1920
http://tinyurl.com/kgpjlfq

Paul Levi’s interventions at the Second Congress of the Communist
International (19 July–7 August 1920)
http://tinyurl.com/pd9fmbf
https://goo.gl/pJHrmS

Paul Levi, “Die politische Lage in Deutschland” (September 1920), Die
Kommunistische Internationale, 2. Jg., 1920, Nr. 14, pp. 114-125.
http://tinyurl.com/nu99qcy

Paul Levi, Brief an Loriot (23. November 1920)
https://www.marxists.org/deutsch/archiv/levi/1920/11/loriot.html

Paul Levi, “Offener Brief der Zentrale der Vereinigten Kommunistischen
Partei Deutschlands vom 8. Januar 1921”, Die Rote Fahne, 8.
Januar 1921.
http://tinyurl.com/qy8q656

Paul Levi, Report to the Executive Committee of the Third
International on the Italian Party Congress at Livorno (Berlin, 20
January 1921)
http://tinyurl.com/p2arqz2

Paul Levi, Der Beginn der Krise in der Kommunistischen Partei und
Internationale. Rede auf der Sitzung des Zentralausschusses der
V.K.P.D. am 24. Februar 1921. Remscheid : Verlagsgenossenschaft
Volksstimme, 1921.
http://tinyurl.com/qje8wjo

Paul Levi, Brief an Lenin (27. März 1921)
https://www.marxists.org/deutsch/archiv/levi/1921/03/brief.html

Paul Levi, Our Path: Against Putschism (April 1921)
https://goo.gl/3o4TXi

Paul Levi, Unser Weg. Wider den Putschismus (April 1921)
https://goo.gl/LDj8QL

The claim that “the most striking feature about Levi’s political career was his consistent failure to deal with what, in the Marxist tradition, has often been termed “ultra-leftism”” is absurd; his position at the October 1919 Heidelberg Congress of the KPD, where he was ready to part with the left wing in defense of participation in parliamentary elections and work in bureaucratized trade unions, was correct, and Lenin’s decision to retain the KAPD as a “sympathizing section” of the Comintern was a mistake later recognized as such (“I clearly see my mistake in voting for the admission of KAPD”, Lenin, Collected Works, Vol. 42, p. 321). On the other hand, the author concedes that “In essentials Levi was absolutely right about the March Action. It was a disaster for the KPD… It undermined the whole united front strategy; whatever decisions the KPD and the International later took, the party could not revert to the situation that had existed at the beginning of 1921; its credibility with SPD members had been destroyed.”

Also correct is the statement that “Luxemburg and Levi are thus made into forerunners of the Popular Front” by Fernbach, who nonetheless has the merit of having translated Levi’s writings. Zinoviev and Béla Kun, the organizers of the “March Action” putsch in 1921, should have been defenestrated at the Comintern’s third congress, not Levi. Zetkin’s words sum up this whole wretched affair: “I consider that it was an illogical decision of the World Congress to have approved the main lines of Levi’s politics and then to have expelled him for a formal breach of discipline. But as a member of the Communist Party and the Third International, I respect this decision, however inept and unjust it may be.”