[BroJoeK]

x: "Most of the Tories in the Carolinas were back country people, not that rich and not really big slave owners..."

Mrsmith tells us it was Dunmore's proclamation which alienated Southern slaveholders, turning them from Tories to Patriots.
That makes sense to me, but it's curious I've not seen that remarked on elsewhere.

x: "Lately some people are trying to sell the idea that fear of slave rebellion was a major force driving the revolution.
So far, though, I don't quite buy it."

Nor would I, since in fact there were no major slave rebellions in the US at that time.
I'd say that Dunmore's proclamation was simply one more nail in the coffin of British rule here, of which the major spikes are listed in the Declaration of Independence, including:

1. The 1774 Massachusetts Government Act abrogating Massachusetts' charter of self government, replacing it with direct British rule.

2. The 1775 Proclamation of Rebellion, effectively declaring war on the colonies.

3. Waging war against Americans, in the DOI's words:
   
   "He has plundered our seas, ravaged our Coasts, burnt our towns, and destroyed the lives of our people.
   He is at this time transporting large Armies of foreign Mercenaries to compleat the works of death, desolation and tyranny, already begun with circumstances of Cruelty & perfidy scarcely paralleled in the most barbarous ages, and totally unworthy the Head of a civilized nation."

Yes, Dunmore's proclamation is referred to in Jefferson's famous deleted paragraph, but the fact it was deleted suggests that was far from foremost in our Founders' minds.

[mrsmith]

In round numbers all international trade south and east of the Blue Ridge went through the port of Charleston SC.
It was huge.
The depredation they suffered in the war was clearly foreseeable, and the benefits they would have during and after it by siding with the British. If Charleston COULD have gone Loyalist it would have, and so would most all that depended upon the port.
On reflection I can see my explanation for Britain continuing the bone-headed manumission policy: no one could later believe a promise from them to protect slavery after that.

Protecting slavery may have been a preeminant reason for war to SC but not to any of the other colonies.