In 1732, Walpole provided a parliamentary subsidy for the new colony of Georgia. While Georgia’s reform-minded trustees envisioned the colony as a refuge for Britain’s poor, Walpole had little interest in social reform; he subsidized Georgia to protect the valuable rice-growing colony of South Carolina. The subsidy, however, did exactly the opposite. Britain’s expansion into Georgia outraged Spanish officials, who were already angry about the rising tide of smuggled British manufactures in New Spain. To counter Britain’s commercial imperialism, Spanish naval forces stepped up their seizure of illegal traders, in the process mutilating an English sea captain, Robert Jenkins.

Yielding to parliamentary pressure, Walpole declared war on Spain in 1739. The so-called War of Jenkins’s Ear (1739–1741) was a fiasco for Britain. In 1740, British regulars failed to capture St. Augustine because South Carolina whites, still shaken by the Stono Rebellion, refused to commit militia units to the expedition. A year later, an assault on the prosperous seaport of Cartagena (in present-day Colombia) also failed; 20,000 British sailors and soldiers and 2,500 colonial troops died in the attack, mostly from tropical diseases.

The War of Jenkins’s Ear quickly became part of a general European conflict, the War of the Austrian Succession (1740–1748). Massive French armies battled British-subsidized German forces in Europe, and French naval forces roamed the West Indies, vainly trying to conquer a British sugar island. Three thousand New England militiamen, supported by a British naval squadron, in 1745 captured Louisbourg, the French fort guarding the entrance to the St. Lawrence River. To the dismay of New England Puritans, who feared invasion from Catholic Quebec, the Treaty of Aix-la-Chapelle (1748) returned Louisbourg to France. The treaty made it clear to colonial leaders that England would act in its own interests, not theirs.