In 2003, the idea that Americans were from Mars and Europeans from Venus stirred up serious conversation about the nature of the transatlantic relationship on both sides of the Atlantic. While useful in prompting discussion, the introduction of pop-psychology terminology into IR lexicon was essentially divisive and not analytically helpful. Kagan relied on journalistic generalization, rather than tested academic methods to support his work. This study rectifies that deficiency, exploring the extent to which Americans are from Mars and Europeans from Venus by deploying the analytical concept of strategic culture for an unbiased analysis of transatlantic drift. Michael J. Williams is a researcher at the Department of Politics and International Relations at the University of Oxford (UK).