A comprehensive Transatlantic Trade and Investment Partnership (TTIP) has important implications for both US-EU bilateral trade and the world trading system. If successful, it could strengthen transatlantic economic relations while also spurring trade reforms that could reinvigorate flagging multilateral trade negotiations. Both sides want the TTIP to be a big deal covering all major components of the commercial relationship. They can achieve the pact's ambitious agenda by (1) broadly aligning their respective trade pacts with South Korea and (2) deepening market access commitments covering both tariff and nontariff barriers to trade in goods, agriculture, and services. KORUS and KOREU FTA precedents are instructive but will need to be supplemented or adjusted in three areas if the TTIP is to succeed: intellectual property issues, sanitary and phytosanitary measures, and the environment. In several other areas KORUS-KOREU differences should be easier to bridge, including services, investment, government procurement, and competition policy.