Am currently reading a quite interesting book, Rosemarie Ostler's Founding Grammars: How Early America’s War Over Words Shaped Today’s Language, which I picked up while roaming in my neighborhood's public library in Washington, D.C. (For all of America's faults, our public libraries cannot be included among them.)
So far as I can tell, the author of Founding Grammars does not deal with the issue of sequence of tenses (I abbreviate it as sot; see also [a] and [b]). The term, fully spelled out or abbreviated, is not mentioned in the index.)
In order to make sure I actually understand sot (which I use "intuitively” while writing), I checked Wikipedia, which states that "[i]n some languages the tense tends to be ‘shifted back’, [JB - note the British usage of the comma after the quotation mark] so that what was originally spoken in the present tense is reported using the past tense (since what was in the present at the time of the original sentence is in the past relative to the time of reporting). English is one of the languages in which this often occurs." (As Russophiles know, such is not the case in Russian.)
But, if you'll allow me to speculate -- "me" being a plain, non-specialist grateful user of a public library -- author Ostler often does not seem to respect the sequence of tenses in English, at least in spirit, in her text, by rather abruptly shifting tenses, within individual paragraphs in order (I speculate) to “liven up” her prose. Among many examples (p. 258):
“Lexicographer Bergen Evans was a vocal champion of the new [Merriam-Webster] dictionary. Several months after Follett’s savage attack, the Atlantic published a rejoinder by Evans. [And now here's the abrupt change of tenses, from past to present:] Evans also tackles the question of what purpose a dictionary is supposed to serve. In answering it, he takes on the major criticisms ….”Authors/grammarians/linguists of the world unite! What are your thoughts on forget-the-sot prose?