Preliminary note: This post is about the emergence of whataboutism and whataboutist in 1978—not about the subsequent uses of those words, in particular not as regards Donald Trump (born 1946), 45^th President of the USA.

The noun whataboutism denotes the technique or practice of responding to an accusation or difficult question by making a counter-accusation or raising a different issue—synonym: whataboutery.

—Cf. also the noun bothsidesism (also bothsideism), denoting the practice by public figures of minimising an objectionable action by heightening actions of other groups so that they will be deemed comparably objectionable.

The noun whataboutism refers to the way in which counter-accusations may take the form of questions introduced by What about —?.

The first known user—perhaps the coiner—of whataboutism was one Lionel Bloch, of Wimpole Street, London, in a letter to the editor published in The Guardian (London and Manchester, England) of Tuesday 23^rd May 1978; Bloch used whataboutism to designate—and denounce—the rhetoric employed by the advocates of the communist regimes:

Sir,—Your leader, “East, West and the plight of the warring rest” (May 18), is the finest piece of “whataboutism” I have read in many years.
Perhaps I ought to explain that “whataboutism” is a condition of the progressive mind which does not tolerate any criticism of Communist autocracy unless those who criticise wear sackcloth and put ashes on their heads for the sins of all non-Communist dictatorships. Nobody must get away with an attack on the Kremlin’s abuses without throwing a few bricks at South Africa; nobody must indict the Cuban police state without castigating General Zia¹, etc.

¹ Muhammad Zia-ul-Haq (1924-88) was a Pakistani general who served as the President of Pakistan from 1978 until his death in 1988, after deposing Prime Minister Zulfikar Ali Bhutto in a military coup.

In the same letter, Lionel Bloch also used—perhaps invented—the noun whataboutist, denoting a person who practises whataboutism (this word is curiously missing from the third edition (2018) of the Oxford English Dictionary):

[…] In blurring the difference between Moscow’s despotism and say the Brazilian regime, the “whataboutist” ignores the fact that the Kremlin is not content to oppress its citizens and the tens of millions of East Europeans under its yoke, but unlike other minor dictatorships throughout the world, insists on exporting its way of life.
It is this incessant expansionism that makes the Soviet regime not only more odious, but much more dangerous. In order to resist it, the free world has no choice but to tolerate occasionally the shortcomings of its less democratic allies. The survival and defence of the western world depends partly on the necessity to put up with the lesser evil.

Two days later, on Thursday 25^th May 1978, the same newspaper published a letter in which one T. A. Wright, of Sevenoaks, Kent, expressed his disagreement with Lionel Bloch’s opinions:

Sir,—It is not strange that Mr Bloch (Letters, May 23), having coined one expression “whataboutism” to relieve his mind of unwelcome pressures, should have tried his hand at another, about which he seems a little more modest in claiming authorship, to the same end—“military dictatorships” are now to be known as “our less democratic allies.”

Lionel Bloch’s letter largely inspired Michael Barnard’s Foreign Affairs column in The Age (Melbourne, Victoria, Australia) of Saturday 17^th June 1978—Barnard used both the nouns whataboutism and whataboutist:

I have long considered there should be a special term to describe that peculiar and woolly state of the “progressive” mind which refuses to tolerate any criticism of Soviet communist repression unless those who criticise first don sackcloth and ashes for the sins of non-communist regimes and dictatorships.
Apparently there is. The disease has been neatly diagnosed by a letter writer in a leading British daily as “whataboutism”, and the afflicted as “whataboutists”.
Congratulations to Lionel Bloch, of Wimpole Street, London […].
[…]
The weaknesses of whataboutism — which dictates that no one must get away with an attack on the Kremlin’s abuses without tossing a few bricks at South Africa, no one must indict the Cuban police State without castigating President Park², no one must mention Irak [sic], Libya or the PLO without having a bash at Israel, &c. — have been canvassed in this column before.

² Park Chung-hee (1917-79) was a South Korean general who served as the President of South Korea from 1963 until his assassination in 1979, after first ruling the country as head of a military junta installed by a coup in 1961.

In this column, Michael Barnard introduced the use of whataboutist as an adjective meaning relating to whataboutism. He titled his column Soviet tyranny and the ‘whataboutist’ virus, and he wrote:

East Germany is central to the whataboutist debate because it has so faithfully followed — and in cases, refined — the repressive evils of its Kremlin mentors.