One of the pillars in the modern case against capital punishment is the international argument which contends that the abolition of the American death penalty is supported by viewing the practice in the global context. America's legacy of racism, societal demand for tough-on-crime approaches, and political maneuvering around the death penalty have resulted in the United States being one of the only free and democratic countries in the world to practice capital punishment. America's unusual position on this issue cannot be fully understood or challenged without being viewed from an international perspective. The international argument has also become much more popular in recent years, but despite its increase in significance the actual effect this argument on American public opinion has gone virtually untested.

The Marshall Hypothesis (that knowledge about the death penalty will reduce support for it) has been measured in terms of the public's receptivity to other important arguments for abolition including racial discrimination, deterrence, and innocence. Each of these arguments and a brief history of the U.S. death penalty debate are described in early chapters in order to provide background for the original research presented in the second half of the thesis. This study adds to the body of research known as "Testing the Marshall Hypothesis" by empirically measuring the impact the international argument has on the opinion of adult American students at a public university in California. Using survey data from over 200 students, this research provides data regarding three questions: (1) is student support for capital punishment affected by exposure to international information regarding the death penalty? If so, (2) to what degree is their support affected, and (3) what pieces of information are most or least compelling? The results of the study lend support to the hypotheses that American university students are receptive to the international argument against capital punishment, that the international argument can alter the opinions of American students to varying and sometimes substantial degrees, and that certain facts are more compelling than others in this regard. The quantitative evidence presented in this study supports Justice Marshall's hypothesis and further strengthens the possibility that the international argument could be a notable contributor in shaping public opinion regarding the death penalty in America.