Antebellum racial attitudes

Were there any whites in the US who had 20th century racial attitutdes? (i.e races are equal)

John Brown seems like a likely candidate.

There were certainly many in the US who thought slavery wrong, going back to the 18th century and beyond. A few early examples:

From the American Anti-Slavery and Civil Rights Timeline.

You can think slavery is wrong and at the same time not think that the races are equal. Like Abraham Lincoln said:

One of the closest might be Thaddeus Stevens, whose attitude can be seen in his epitaph (in Lancaster’s black cemetery)