… is from page 26 of Bruce Caldwell’s superb Introduction to the 2007 Definitive Edition (Bruce Caldwell, ed.) of F.A. Hayek’s classic 1944 book, The Road to Serfdom:
Hayek was trying to show his readers that planning, everyone’s favorite remedy for the ills of the world, might sound good in theory, but would not work out in practice (or, at least, not unless the western democracies were prepared to accept severe constraints on personal liberty of the sort on display in the systems against which they currently [in 1944] were fighting).