Let’s blame the British
The phrase’s origin is uncertain, but it likely got its start in British politics, where the phrase “under a bus” was already in use as a metaphor for misfortune or a conveniently-timed accident. Let’s explore the meaning of ‘Throw someone under the bus’ first.
What does it mean to throw someone under the bus? Well, for the extremely criminally minded, it may have the literal meaning of shoving a person under the carriage of a large motor vehicle. Yet given the relative prevalence of this expression (and the relative lack of such assaults), it seems safe to assume that there is a highly figurative meaning involved.
Meaning
To throw someone under the bus is to criticize, blame, or punish them, especially in order to avoid blame or gain an advantage. People so thrown are typically in a vulnerable position. It can also be interpreted as “to betray or sacrifice a person, particularly for the sake of one’s own advancement, or as a means of safeguarding one’s own interests”
Popularity
Throw under the bus became enormously popular in The States during the 2008 presidential election, although it had a certain degree of prominence prior to that among sports journalists. When it began being used considerably more in the mid and late-2000s, there was a good deal of interest in the origins of the phrase, and so as a result the Internet is now replete with wrong information on this subject.
Origins of the expression ‘Throw someone under the bus’
The earliest written record we have of under the bus being used as a colloquialism comes in 1980, in reference to a British politician.
The reaction of the Right to the events of the last year have varied depending on where in the spectrum they stand. Some still pin their hopes on the “under the bus” theory which has Mr. Foot being forced by ill health—or just the pressures of the job—to give way to Mr. Healey before the next election.
— Elinor Goodman, The Financial Times (London), 10 Dec. 1980
While the above use certainly has the placement of a person under a bus being used in a metaphorical fashion, it lacks the sense of betrayal that is a part of its current usage. That comes less than two years later, again found in British politics.
The Conservative benches listened to her in silence. She was in deep trouble and the lobbies hummed with the prospect of her departure. President Galtieri had pushed her under the bus which the gossips had said was the only means of her removal.
— Julian Critchley, The Times (London), 21 June 1982
The expression throw/push/shove someone under the bus dates to Britain in the late 1970s or early 1980s, especially when considering that there was already a similar under a bus expression in use there.
There is an amusing little parlour game much favoured by politicians. It is called “Let’s kill the Leader,” and, when played by Labour loyalists, it begins “Supposing Harold Wilson were to go under a bus…”
— Hugh MacPherson, The Spectator (London), 23 Jan. 1971
