Following the failure of the revolutions, he and many other intellectuals and leaders fled to the United States, where he became editor of the Illinois Staats-Zeitung and eventually served as a member of the United States House of Representatives from Illinois.

He was sentenced to imprisonment for life after the failure of the revolution, but sought refuge in the United States via Switzerland.

He established Der Leuchtturm, a German anti-slavery journal, in Pottsville, Pennsylvania.

After leaving Congress, he engaged in literary and historical research designed to compare and contrast the American and European codes of criminal procedure.

In this line of work he published a report of the trial of the assassin of President Garfield, and a history of the celebrated case of Kring v. Missouri (see List of United States Supreme Court cases, volume 107).