In the briny aftermath of Hurricanes Katrina (2005), Ike (2008), Sandy (2012), and Matthew (2016), community leaders along the East and Gulf Coasts of the United States are contemplating a radical shift in the planning, design, and management of their coastal zones. Breaking with a century-long tradition of coastal grey infrastructure planning, many of those communities--along with the U.S. Army Corps of Engineers (USACE)--are shifting their attention and their investments away from conventional forms coastal infrastructure and towards "nature-based strategies", or non-structural forms of coastal protection. But why do some communities opt for a softer, greener coast while others double-down on their investments in grey infrastructure? How do the nature-based strategies under consideration compare, performatively, to the more conventional forms of coastal protection? Using a comparative case study research design, I posit that three forces explain how and why Galveston, Norfolk, New York City and other communities along the East and Gulf Coasts develop their approach to coastal protection. The first is a product of each community's engineering legacy, or the historical approach to flood protection that developed during the 19th and 20 centuries and the culture that organized around those forms. The second is function of resilience politics, or the value judgements about who gets to stay and who must retreat, who is worthy of protection and who is not along the American coast. The final is a product of who leads the political coalition behind each community's resilience planning--with a particular focus on the differences between design-led and engineering or planning-led efforts. This dissertation advances the theory and practice of coastal planning and design and provides a framework for action along the Gulf and East Coasts of the U.S.