Law plays a significant role in contemporary transatlantic relations outside of the bilateral context which, from the perspective of EU external relations law, might seem neither conventional nor apparent. Non-bilateral transatlantic relations increasingly deploy law as a communication tool between the two legal orders. For example, in 2011, the US intervened informally and anonymously in the formulation of EU legislation, while the US House of Representatives passed legislation to prohibit the impact of EU law upon the US legal order. Another example is constituted by EU amicus curiae submissions before the US Supreme Court in death penalty cases. The so-called Brussels effect is also the subject of recent scholarship, assessing the perceived spillover effect of EU regulatory standards onto US rules. The paper provides many vivid examples of the variable institutional and legal components of transatlantic relations not usually accounted for in scholarship on transatlantic relations.