He notably presided over the 1861 trial of Nathaniel Gordon, the only person to be convicted and executed in the United States for illegal slave smuggling.

He was confirmed by the United States Senate on March 12, 1860, and received his commission the same day.

[2] In sentencing Gordon, Shipman said: Let me implore you to seek the spiritual guidance of the ministers of religion; and let your repentance be as humble and thorough as your crime was great.

Think of the sufferings of the unhappy beings whom you crowded on the Erie; of their helpless agony and terror as you took them from their native land; and especially of their miseries on the ---- ----- place of your capture to Monrovia!

In the just and generous heart, the humble and the weak inspire compassion, and call for pity and forbearance.