… is from pages 223-224 of Douglas Irwin’s 2017 book, Clashing Over Commerce  (footnote deleted; brackets original to Irwin; links added):
Recognizing that it could benefit from further advice on postwar financial matters, Congress created the position of the special commissioner of the revenue in 1866. David A. Wells , the chairman of the earlier revenue commission, was appointed to a four-year term. Although tariff policy was viewed as the most politically sensitive postwar economic issue, Republicans believed that Wells – a well-known supporter of protection and a friend of the tariff activist Henry Carey  – was a safe appointment. However, after having spent time in Washington, Wells was shocked to see that powerful special interests operating behind the scenes were having an inordinate influence on government policy. He was further surprised by the fact that politicians served those interests for what he saw as selfish political reasons and not for the best interests of the country. In July 1866, in private correspondence, Wells remarked, “I have changed my ideas respecting tariffs and protection … I am utterly disgusted with the rapacity and selfishness which I have seen displayed by Penn[sylvania] people, and some from other sections on this subject.”
DBx: Wells – in large part because he saw up-close and with eyes wide open, and smelled with nostrils unclogged, the true nature and purpose of trade restrictions – became in time a free trader .