One hundred and fifty years ago today, the war for the Union began broadening to a war against slavery with the passage by Congress of a new Article of War:
An Act to make an additional Article of War.
Be it enacted by the Senate and House of Representatives of the United States of America in Congress assembled, That hereafter the following shall be promulgated as an additional article of war for the government of the army of the United States, and shall be obeyed and observed as such:
Article —. All officers or persons in the military or naval service of the United States are prohibited from employing any of the forces under their respective commands for the purpose of returning fugitives from service or labor, who may have escaped from any persons to whom such service or labor is claimed to be due, and any officer who shall be found guilty by a court-martial of violating this article shall be dismissed from the service.
SEC. 2. And be it further enacted, That this act shall take effect from and after its passage.
From the beginning of the War, slaves had been escaping into Union lines. What to do with the escaped slaves had been a perplexing question with the responses of Union officers ranging from returning slaves to their masters, to setting slaves free. Congress had passed the Confiscation Act of 1861 the previous August which permitted Union forces to confiscate any property, including slaves, being used in support of the rebellion. With the passage of this Article of War Congress now made it clear that all Union forces were not to prop up slavery by returning slaves to their masters, a big step towards emancipation, and a recognition that the War itself was kiling the Peculiar Institution.