With emphasis he wrote, “Intervention is a limited order by a social authority forcing the owners of the means of production and entrepreneurs to employ their means in a different manner than they otherwise would.”
Mises pushed the distinction between interventionism and state socialism hard .. True, he said, some interventionists believe that system is temporary. Nevertheless, “all its followers and advocates fully agree that it is the correct policy for the coming decades, even the coming generations.”
The other notable point is that Mises assumed that interventionists were public-spirited. This doesn’t mean he necessarily thought every interventionist had good intentions, but he was willing to grant this for the sake of argument ..
The upshot for Mises is the incoherence and intrinsic instability of interventionism. It is incoherent because it “contradicts economic logic.” It is unstable because the third way can’t be sustained. “Government either abstains from limited interference with the market forces, or it assumes total control over production and distribution. Either [laissez-faire] capitalism or socialism; there is no middle of the road.”
Somewhat paradoxically, therefore, it appears that the product of interventionism, the mixed economy, though unstable, is likely to be more enduring than the pure forms of either collectivism or capitalism, offering as it does a much wider range of (ultimately futile) adaptive forms than either of its rival systems. The inherent instability of interventionism thus drives the mixed economy through a variety of transformations that are denied to the other systems.