US History 11, Barriers to Equal Opportunity, PROGRESS CHECKPOINT

...The slaveholders blinded them to this competition by keeping alive their prejudice against the slaves as men--not against them as slaves. They appealed to their pride, often denouncing emancipation as tending to place the white working man on an equality with negroes, and by this means they succeeded in drawing off the minds of the poor whites from the real fact, that by the rich slave-master, they were already regarded as but a single remove from equality with the slave. The impression was cunningly made that slavery was the only power that could prevent the laboring white man from falling to the level of the slave's poverty and degradation.

From Life and Times of Frederick Douglass: His Early Life as a Slave, His Escape From Bondage, and His Complete History to the Present Time, p. 180 (published 1881)

Frederick Douglass on the “craftiness” of slaveholders

The slaveholders, with a craftiness peculiar to themselves, by encouraging the enmity of the poor laboring white man against the blacks, succeeded in making the said white man almost as much a slave as the black slave himself. The difference between the white slave and the black slave was this: the latter belonged to one slaveholder, and the former belonged to the slaveholders collectively. The white slave had taken from him by indirection what the black slave had taken from him directly and without ceremony. Both were plundered, and by the same plunderers. The slave was robbed by his master of all his earnings, above what was required for his bare physical necessities, and the white laboring man was robbed by the slave system, of the just results of his labor, because he was flung into competition with a class of laborers who worked without wages. The slaveholders blinded them to this competition by keeping alive their prejudice against the slaves as men--not against them as slaves. They appealed to their pride, often denouncing emancipation as tending to place the white working man on an equality with negroes, and by this means they succeeded in drawing off the minds of the poor whites from the real fact, that by the rich slave-master, they were already regarded as but a single remove from equality with the slave. The impression was cunningly made that slavery was the only power that could prevent the laboring white man from falling to the level of the slave's poverty and degradation.

From Life and Times of Frederick Douglass: His Early Life as a Slave, His Escape From Bondage, and His Complete History to the Present Time, p. 180 (published 1881)