Mises on public works

"It is obviously futile to attempt to eliminate unemployment by embarking upon a program of public works that would otherwise not have been undertaken. The necessary resources for such projects must be withdrawn by taxes or loans from the application they would otherwise have found. Unemployment in one industry can, in this way, be mitigated only to the extent that it is increased in another. From whichever side we consider interventionism, it becomes evident that this system leads to a result that its originators and advocates did not intend and that, even from their standpoint, it must appear as a senseless, self-defeating, absurd policy."
Liberalism, Ludwig von Mises