Why did Britain change its strategy to focus on the Southern colonies in the summer of 1778?

Answer

First, the war, which had primarily been fought north of Pennsylvania previously, had essentially become a stalemate by that time. While seldom losing battles, the British had failed to destroy the Continental Army in the field.

Second, British military leaders believed that the southern colonies were full of Loyalists who would flock to the king's standard once British troops showed up.

The French allied with the colonials, and the British believe they had supporters in the south.

Explanation:

The French signed a treaty with the colonials in 1778 which forced the British to rethink their tactics.  They were now having to fight both the newly formed Americans and the French.  The British falsely believed they had more colonial supporters in the south, so began to focus their efforts there in attempt to subvert the French involvement.  

what are the others?

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