Your former President strongly disagreed with you.
One of the positions laid down by the honorable Senator from Kentucky, and which he denominated as one of his two truths, was, that slavery was excluded from the Territories of California and New Mexico by a decree of Nature. From that opinion I dissent. I hold that the pursuit of gold-washing and mining is better adapted to slave labor than to any other species of labor recognized among us, and is likely to be found in that new country for many years to come. I also maintain that it is particularly adapted to an agriculture which depends upon irrigation. Till the canals are cut, ditches and dams made, no person can reclaim the soil from Nature; an individual pioneer cannot settle upon it with his family, and support them by the product of his own exertion, as in the old possessions of the United States, where rain and dew unite with a prolific soil to reward freely and readily the toil of man. It is only by associated labor that such a country can be reduced to cultivation. They have this associated labor in Mexico under a system of peonage. That kind of involuntary servitude, for debt I suppose, cannot long continue to exist under American institutions; therefore the only species of labor that can readily supply its place under our Government would, I think, be the domestic servitude of African slavery; and therefore I believe it is essential, on account of the climate, productions, soil, and the peculiar character of cultivation, that we should during its first settlement have that slavery in at least a portion of California and New Mexico.
And you’re still a moron.
As for Gold Mining and Washing? They had 80 years they could have had slaves in New Mexico territory, but they didn't.
Real world data beats ginned up Theory every day of the week.
And if you said "your former President" to me in person, I would hit you in your obnoxious mouth.