(This post completes my three‐part discussion of the “regime uncertainty” hypothesis, according to which the New Deal hampered recovery by causing businessmen to fear policy changes that might render their investments unprofitable. Links to the previous posts about regime uncertainty, and to the other posts of my series on The New Deal and Recovery , occur at the end of this post.) Proving It Nothing seems more plausible, on its face, than the claim that policy shocks like those we’ve surveyed, coming as they did from a president who was often openly hostile to businessmen, discouraged investment. It’s no doubt largely owing to this, and to businessmen’s own insistence that New Deal policies frightened them, that the regime uncertainty hypothesis has gained adherents among economists.