Robert Leeson asks for a history of external pressures and unscrupulous
methods. A broader picture of the matter yields interesting results imo. 

Samuelson published in 1948, I turn to another giant created at that time -
Fernand Braudel - who published on the history of capitalism in his
‘Mediterranean’ in 1949 

In the 1966 edition of Mediterranean (p. 902) he seems to give his own view
of the mid century change here:

FB  <Nowadays we have two fairly well established 'chains' to choose from,
one built up by the research of the last twenty or thirty years – the chain
of economic events and their short-term conjunctures; the other catalogued
over the ages – the chain of political events in the wide sense.   For us,
there will always be two chains – not one..... we should beware of falling
into the trap of naively assuming that one can explain the other>

Thus the Braudel aim is not to disguise ideology behind a technical
presentation.  Much more fundamentally, he lays the ground for an
intellectual canvas cleaning in which traditional ideological concerns are
no longer relevant at all, and can be banished from the scene.  A modern
Macbeth, he fractures reality itself in pursuit of his goal.

Braudel’s Post-Modern/Post-Rational position surely derives primarily from
Febvre, but parallels moves were also under way in the UK by Wittgenstein,
promoted by Keynes.

The major event I would point up in 1948 was the abrupt shunting of UNESCO
from London to Paris – after Julian Huxley’s unexplained mid term
resignation.  Huxley was closely associated with the prominent British
ideological group Hayek dismissed as intellectuals – Wells, Russell, Bernal,
Haldane, Needham etc.  All these people had interests in science and
socialism, and acted to weld leftist economic ideology to scientific
objectivity in the public mind, promoting socialism as the rational path. 
Keynes, clearly and undeniably, saw Russell’s reliance on rationality in
political life as ‘ludicrous’, thus was apparently an intellectual enemy of
this Wells grouping, alongside Hayek. 

Braudel was a great beneficiary of the UNESCO move to Paris.  For me the
bottom line is that rather than (legitimately) seeking to dissolve the link
between scientific objectivity and socialism, Braudel and Keynes
(illegitimately) acted to undermine rationality itself – setting us on the
road to Foucault etc.

Lazarsfeld came up only peripherally in the textbook discussion – but he
also worked on propaganda for the Ford Foundation, and on the efficacy of
lying for the US military.  Braudel seems to have won what Lazarsfeld calls
<a machine> out of these events (PFL: you need a machine to advance an
intellectual agenda .... the money of government and commerce)  Braudel got
French government money, and international prestige, via UNESCO.  A further
one million dollar grant came his way from the Ford Foundation, awarded for
his political influence rather than his academic achievement, and on
condition, it seems, that he wrote the syllabus for his new institute in
collaboration with Lazarsfeld.

This is just a small part of the web – that Needham, apart form his interest
in science and the political economy, was also a controversial weapons
inspector, is another interesting aspect of this mid century transformation.

Corroborations available - please ask

Rob Tye