As a leader of the Global South with the longest border with a Global North country, Mexico leveraged its strategic position to influence international dynamics significantly. This study examines U.S.-Mexican relations during the Carter administration (1977-1981) and the presidency of José López Portillo (1976-1982), highlighting three critical developments. Firstly, Mexico's ability to influence the appointment of U.S. ambassador Patrick J. Lucey showcased its diplomatic leverage. During Carter's administration, Washington needed Mexico to increase its oil output due to Middle Eastern instability and anti-American sentiment in Iran. To meet this objective and appease President López Portillo's request for a non-hyphenated American ambassador, Carter appointed Lucey, significantly impacting bilateral negotiations. Secondly, the discovery of oil in Mexico elevated its international status, offering the U.S. closer access to crucial resources and strengthening alliances. This is linked to the resource curse, where reliance on natural resources led to economic instability and political challenges. Lastly, the dynamic between Carter and López Portillo showed initial cooperation but led to strained relations. Mexico’s asylum to the Shah of Iran during the American hostage crisis in Tehran caused significant tension and contributed to Carter's electoral defeat. Using sources like New York Times articles, López Portillo's speeches, U.S. Office of the Historian documents, and the Wilson Center, this research aims to provide insights into Mexico's diplomatic strategies and their impact on global economic and political landscapes during this critical period.