James Berret was elected Mayor of Washington in 1860. In 1861, when the civil war broke out, Congress enacted a law requiring all officers of the government, national, state and municipal, to take the oath of allegiance to the United States. Mr. Berret by reason of his position as mayor was president of the board of police commissioners of Washington and Georgetown. When the oath was tendered to the members of the board Mr. Berret declined to take it. He said that while he was a state's right man, he was also a strong Union man, and further declared that there was no necessity for his taking the oath when he had already subscribed to it when inaugurated as mayor.

This position was not satisfactory to the government and accordingly Mayor Berret was arrested in August 1861 and taken to Fort Lafayette, N.Y. His residence was searched, but no evidence of his complicity or sympathy with the rebellion was discovered. In September Berret was released from prison and he resigned his position as Mayor.