This.
The North decided to use the model of desperate Irish Immigrants who could be worked to death cheaper than it would cost them to keep slaves, and if their workers died, there was no problem. More would be coming off the boat soon anyways.
New York was settled mostly by the English, and they hated the Irish anyway.
The North, Great Britain, and other major manufacturing countries could have expedited the end of slavery in the South without war by refusing to buy slave-produced cotton. With no customers, the South would have stopped growing cotton they could not sell.
The North wasn't upset that their cotton was produced by Slaves, they were upset by the fact that they were going to lose their money stream from Europe, which thanks to their gaming of the laws, was routed through New York instead of it's natural course of trade with the areas of the country producing the bulk of the exports.
Just another of DiogenesLamp's cockamamie historical theories.
In fact, Irish Catholics were only 1.5% of the US population in 1775 and the great migration of millions only began after the Famine of 1845-1852.
So Northern abolition began long before there were huge numbers of Irish Catholics to man the industrial revolution.
Of course, Scots-Irish are a very different story because, first they were Protestants, second, they served in the Continental Army in huge numbers thereby earning respect and gratitude from their fellow citizens, and third, they mostly settled as far back in the back-woods as they could get -- they were the original "rugged individualists" and bought into the new Constitution 100%.
DiogenesLamp: "The North wasn't upset that their cotton was produced by Slaves, they were upset by the fact that they were going to lose their money stream from Europe, which thanks to their gaming of the laws, was routed through New York instead of it's natural course of trade with the areas of the country producing the bulk of the exports."
Possibly true of Northern Big City Democrats, but contrary to DiogenesLamp's frequent claims, those Democrats were not really calling the shots in early 1861.
Republicans then as today were a different breed of citizens -- mostly small town & rural, independent minded, they loved their Constitution and they hated slavery.
And they were not willing to accept their Union being trashed over bogus claims of "oppression" or "injury" when nothing like that had happened.
Even a Doughfaced Northern Democrat like outgoing President Buchanan (from small-town Pennsylvania) was willing to accept, reluctantly, unilateral secessions but not Jefferson Davis' attack on Fort Sumter.
Buchanan was not moved by supposedly "losing their money stream", but rather by Jefferson Davis' blatant military aggression.