From, 'Homage To Catalonia',by,George Orwell

Finally, as to the charge that the P.O.U.M. was 'Trotskyist'. This word
is now flung about with greater and greater freedom, and it is used in a
way that is extremely misleading and is often intended to mislead. It is
worth stopping to define it. The word Trotskyist is used to mean three
distinct things:


(i) One who, like Trotsky, advocates 'world revolution' as against
'Socialism in a single country'. More loosely, a revolutionary
extremist.

(ii) A member of the actual organization of which Trotsky is head.

(iii) A disguised Fascist posing as a revolutionary who acts especially
by sabotage in the U.S.S.R., but, in general, by splitting and
undermining the Left-wing forces.


In sense (i) the P.O.U.M. could probably be described as Trotskyist. So
can the English I.L.P., the German S.A.P., the Left Socialists in
France, and so on. But the P.O.U.M. had no connexion with Trotsky or the
Trotskyist ('Bolshevik-Leninist') organization. When the war broke out
the foreign Trotskyists who came to Spain (fifteen or twenty in number)
worked at first for the P.O.U.M., as the party nearest to their own
viewpoint, but without becoming party-members; later Trotsky ordered his
followers to attack the P.O.U.M. policy, and the Trotskyists were purged
from the party offices, though a few remained in the militia. Nin, the
P.O.U.M. leader after Maurin's capture by the Fascists, was at one time
Trotsky's secretary, but had left him some years earlier and formed the
P.O.U.M. by the amalgamation of various Opposition Communists with an
earlier party, the Workers' and Peasants' Bloc. Nin's one-time
association with Trotsky has been used in the Communist press to show
that the P.O.U.M. was really Trotskyist. By the same line of argument it
could be shown that the English Communist Party is really a Fascist
organization, because of Mr John Strachey's one-time association with
Sir Oswald Mosley.

In sense (ii), the only exactly defined sense of the word, the P.O.U.M.
was certainly not Trotskyist. It is important to make this distinction,
because it is taken for granted by the majority of Communists that a
Trotskyist in sense (ii) is invariably a Trotskyist in sense (iii)--i.e.
that the whole Trotskyist organization is simply a Fascist
spying-machine. 'Trotskyism' only came into public notice in the time of
the Russian sabotage trials, and to call a man a Trotskyist is
practically equivalent to calling him a murderer, agent provocateur,
etc. But at the same time anyone who criticizes Communist policy from a
Left-wing standpoint is liable to be denounced as a Trotskyist. Is it
then asserted that everyone professing revolutionary extremism is in
Fascist pay?