This Independent Study investigates the effect of political party on Congressional roll-call votes on public lands policies and how this effect changes over time. Many scholars have documented the role that political party plays in influencing roll-call voting behavior, but this study fills a gap with regards to public lands policy specifically. I argue that, over time, political party has become more predictive of whether or not a member of Congress will vote in favor of public lands policies. The results of my study show that, beginning around the 1990s, Senators began to divide along party lines on public lands policies. Democratic Senators voted increasingly in favor of public lands policies, while their Republican counterparts became less likely to support these policies over time. Today, the two parties are nearly entirely polarized on the issue. However, there are Republicans today who vote against their party and in favor of public lands policies. I argue that, for these outlying Senators, constituency is a driving force behind their decisions. When talking publicly about public lands, I found that Republican Senators with high vote scores frequently make appeals to their constituency by referencing the lands in their state.


van Doorn, Bas


Political Science


American Politics


roll-call vote, public lands, national parks

Publication Date


Degree Granted

Bachelor of Arts

Document Type

Senior Independent Study Thesis Exemplar



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