Mao’s dissertation focuses on foreign trade policy and international politics at the time of slavery. It discusses how the British trade liberalization policy impacted U.S. slavery and electoral returns in the middle of the 19^th century. The work first identifies the causal relationships between the Repeal of the British Corn Laws and slavery in the U.S. southern cotton states. Then, it argues that these changes in the trade regime significantly affected the U.S. presidential and congressional electoral returns from 1840 to 1860.

In addition to her solid research work, Marcie has taught some principles of economics courses for a number of years, including a course in Global Economics in the China Summer Program 2019. The school noted that Mao's teaching support has been "an enormous asset to the School and its students."