Is the U.S. Justified in Considering a North American Alliance Doctrine? The United States’ colossal defense spending (3.4–3.7% of GDP, $778–968 billion from 2020–2024) has bankrolled global security, enabling allies like Japan, Germany, South Korea, Canada, and Australia to prosper with lean defense budgets (1.4–2.5% of GDP) while forcing rivals like Russia (7.1%, $149 billion in 2024) to overspend. Frustration with European NATO allies—only 11 of 31 met the 2% GDP target in 2023—spurs interest in a North American alliance doctrine with Canada, Greenland, Mexico, and Central American states to secure the region while reducing NATO reliance. This note explores the strategic, economic, political, and geopolitical dimensions of this shift, including benefits to Canada and Greenland, and the roles of Mexico and Central America. While a regional focus could enhance security and economic ties, it risks weakening global influence. The reflection assesses whether this doctrine is a strategi...