Who referred to the amendments of reconstruction as a “great constitutional revolution”?

This was coined by Republican leader Carl Schurz.  He was a German revolutionary and an American journalist, statesman, and reformer. He journeyed to the United States after the German revolutions of 1848 til 1849 and became a noticeable member of the Republican Party. After serving as a Union general in the American Civil War, he helped originate the short lived Liberal Republican Party and became a prominent supporter of civil service reform. Schurz represented Missouri in the United States Senate and was the 13th United States Secretary of the Interior.

The american civil war