In the first half of the 20th Century, an "Unwritten Alliance" amicably existed between the United States and Brazil. This is not true today. Some suggest the two countries' strategic interests continue to diverge. This perception of divergence must be reversed. In response to Brazil's emergence as a world power, the United States must overhaul its bilateral security strategy for the world's 7th largest economy and Latin America's largest military. Brazil's real genuine concerns with sovereignty and reciprocity along with negative American stereotypes that permeate Latin American culture will complicate this task. Nonetheless, there is opportunity to bring the U.S. and Brazil's diplomatic and security relationships closer together to build a strategic partnership based on common interests throughout the world. This work proposes ways to strengthen these relationships through pursuit of common areas of interest. Failure to substantially improve U.S. relations with Brazil will cause its leaders to seek more advantageous relationships elsewhere--to the detriment of the United States.