Why people collaborate to achieve their political objectives is one enduring question in public policy. Although studies have explored this question in low-intensity policy conflicts, a few have examined collaboration in high-intensity policy conflicts. This study asks two questions: What are the rationales motivating policy actors to collaborate with each other in high-intensity policy conflicts? What policy actor attributes are associated with these rationales? This study uses questionnaire data collected in 2013 and 2014 of policy actors from New York, Colorado and Texas who are actively involved with hydraulic fracturing policy debates. The results show that professional competence is the most important rationale for collaborating, whereas shared beliefs are moderately important, and financial resources are not important. Policy actor attributes that are associated with different rationales include organisational affiliation and extreme policy positions. This article concludes with a discussion on advancing theoretical explanations of collaboration in high-intensity policy conflicts.