What most likely explains the change in the amount of currency in circulation between 1865 and 1870?

The increase in the amount of currency in circulation between 1865 and 1870 can be primarily attributed to the withdrawal of "greenbacks" from circulation. After the Civil War, there was a significant public debate over the use of greenbacks, which were paper currency issued by the U.S. government not backed by gold or silver at the time. The government aimed to stabilize the economy and control inflation, leading to policies that included reducing the number of greenbacks in circulation. As a result, the value of the existing currency increased, and the government's efforts to retract them played a vital role in this transition.

During this period, economic policy was heavily influenced by post-war inflation concerns and broader economic recovery. The decisions made regarding the issuance and withdrawal of currency directly impacted wealth distribution and economic stability. Understanding the fluctuation of currency during this time highlights the complexities of the American economy's adjustment after the war and the government's efforts to manage monetary policy effectively.