While it is true that the opposition to slavery in California was nearly unanimous (the provision in the Constitutional Convention to that effect was adopted unanimously, without any substantive debate), it was not for any moral abhorrence of slavery. This was made clear by the subject which took up the largest part of the 1849 debate, a proposal to “prohibit free persons of color from immigrating to and settling in this State, and to effectually prevent the owners of slaves from bringing them into this State for the purpose of setting them free." As one of the members of the Convention, O.M. Wozencraft, put it:

“If there was just reason why slavery should not exist in this land, there is just reason why that part of the family of man, who are so well adapted for servitude, should be excluded from amongst us . . . in order that I may thereby protect the citizens of California in one of their most inestimable rights-the right to labor. This right is not only valuable, but it is a holy commandment-‘ by the sweat of thy brow shalt thou earn thy daily bread.’ I wish to inculcate this command, and encourage labor. I wish, so far as my influence extends, to make labor honorable; the laboring man is the nobleman in the true acceptation of the word and I would make him worthy of his high prerogative, and not degrade him by placing him upon a level with the lowest in the scale of the family of man. . . . I desire to protect the people of California against all monopolies —to encourage labor and protect the laboring class. Can this be done by admitting the negro race? Surely not; for if they are permitted to come, they will do so-nay they will be brought here. Yes, Mr. President, the capitalists will fill the land with these living laboring machines, with all their attendant evils. Their labor will go to enrich the few, and impoverish the many; it will drive the poor and honest laborer from the field, by degrading him to the level of the negro.”

John Ross Browne, Report of the Debates in the Convention of California, on the Formation of

the State Constitution, in September and October, 1849 (J. T. Towers, D.C. 1850), available

online at: http://name.umdl.umich.edu/AEW7910.0001.001

and Lucile Eaves and J. David Sackman, A History of California Labor Legislation: Revised and Updated Centennial Edition (Queen Calafia Publishing 2012)

http://www.queencalafiapublishing.com/a-history-of-california-labor-legislation.html