Thinking about the long term viability of slavery in an independent CSA [1862, no Emancipation, foreign recognition, Democrat smash victory at the polls], I came upon a question. If the south is formally recognized as an independent republic, the Fugitive Slave Law of 1850 would logically no longer apply. What effect would this have on the numbers of runaway slaves, relative to the continuing war OTL? In my understanding, the North was quite racist during the period, but rather than dominative, hierarchical racism like you see in the south, it was exclusionary in character. Given that they didn't want black people in the territories, would the moderate Republicans make common cause with the Democrats to keep mass fugitive slave migration into the north, or did they have neither the will or means to exclude black people from the north?