Why did the authors of the southern manifesto claim that chief justice earl warren’s decision was a threat to the us constitutional order?

The reason why the authors of the Southern Manifesto claimed that Chief Justice Earl Warren’s decision was a threat to the US constitutional order was because this document was written in the South in 1956 and attempted to push back against Brown V. Board of Ed. (which Warren had presided over), since this case stated that racial segregation in school was illegal.