The British in late 1779 embarked on a new strategy based on the assumption that most Southerners were Loyalists at heart. General Clinton withdrew the British garrison from Newport, and marshalled a force of more than 10,000 men that in the first half of 1780 successfully besieged Charleston, South Carolina. In June 1780 he captured over 5,000 Continental soldiers and militia in the single worst defeat of the war for the Americans. Washington had at the end of March pessimistically dispatched several regiments troops southward from his army, hoping they might have some effect in what he saw as a looming disaster.