EDNOTE:  In my strivings for ever greater degrees of triviality, I share the following:
 
Chapter XIII of SPEAK MEMORY relates VN's years at Cambridge. In section 3, VN writes of his encounters with "Nesbit" (a character based in part on fellow student R.A. Butler) as an example of  idealistic "fellow travelers" who took an excessively benevolent view of Soviet Russia in the early twenties. On p. 263, he writes "[Nesbit] maintained  that the reason for what he demurely called 'less variety of opinion' under the Bolsheviks than in the darkest  Tsarist days was 'the want of any tradition of    free speech in Russia,' a statement he got, I believe, from the sort of fatuous 'Dawn in Russia' stuff that eloquent English and American Leninists wrote in those years."
 
The words   ('less variety of opinion' & 'the want of any tradition of  free speech in Russia,'  attributed to "Nesbit"  are not "Nesbit's'  but drawn by VN verbatim from "Dawn in Russia" by American writer-journalist Waldo Frank. The 1932 book (Scribner's: New York & London, p. 163)  appeared only   some 10-12 years after  VN's undergraduate discussions  with Nesbit/Butler, later a Tory deputy prime minister. Nabokov's anachronism is, of course, inconsequential, but should make the reader of SPEAK MEMORY alert to other possible slips. 
 
As a side issue, one might wonder where VN read or browsed Frank's book. It would not have been easily available on the continent and it is likely that VN encountered it only after his arrival in the U.S. The SM chapter in question was written in 1950 and VN may have found Frank's volume on a library shelf. The Cornell library lists 35 volumes by Frank, but not "Dawn in Russia."  Nor is "Dawn in Russia" among the dozen Frank volumes in the Wellesley libray. Frank (1889-1967), a man of wide cultural and political interests His "Dawn in Russia" is his account of a tourist trip to Russia circa 1930 and is by no means a whitewash.  Frank was well aware of the brutality of the Soviet regime, although hopeful for Russia's future.

Memoirs of Waldo Frank. Edited by Alan Trachtenberg. Introd. by Lewis Mumford.

Database: Cornell University Library
Author/Creator: Frank, Waldo David, 1889-1967.
Title: Memoirs of Waldo Frank. Edited by Alan Trachtenberg. Introd. by Lewis Mumford.
Published: [Amherst] University of Massachusetts Press, 1973.

Location: Olin Library
Call Number: PS3511.R195 Z59