This article is about James Robertson the Trotskyist political figure. For the founder of Nashville, see James Robertson (early American)

James Robertson is the National Chairman of the Spartacist League in the United States and leader of the International Communist League (Fourth Internationalist) which is an international oganization of small Trotskyist groups.

He is a Scottish descendant.

He studied chemistry at the University of California, Berkeley in his youth.

Robertson was a member of the youth wing of Max Shachtman's International Socialist League in the 1950s. He became disillusioned as that group moved away from Marxism to merge with the Socialist Party of America and, in 1957 he and a group led by Tim Wohlforth left the ISL to join the Socialist Workers Party (US).

In 1963 he and Wohlforth led the Revolutionary Tendency within the SWP which disagreed with the party's analysis of the Cuban Revolution and with plans by the SWP to unify with the International Secretariat of the Fourth International from which it had split in 1953 (see Fourth International) and which Robertson and Wohlforth characterized as "Pabloite". The merger took place forming the new United Secretariat of the Fourth International and the Revolutionary Tendency was expelled in 1964, the year after the USFI's creation.

The RT initially joined with the International Committee of the Fourth International (which the SWP had left) and came under the influence of Gerry Healy of Britain's Socialist Labour League but disagreements emerged between Robertson and Wohlforth (and their followers) and Robertson and his group were expelled and formed the Spartacist League. Another former SWP member, Lyndon LaRouche (known then as Lyn Marcus) was also involved with the Spartacist League initially but he split to form his own group.