Why labor works alongside environmental groups to advocate climate policies in some times and places but not others. Climate policy research increasingly identifies organized labor as a barrier to climate policy but also a potential supporter and calls for climate advocates to build coalitions with labor. Getting to Work on Climate Policy explains why labor works alongside environmental groups to advocate climate policies in some times and places but not others, drawing on case studies of four states in the American West: California, Colorado, Oregon, and Washington. Using original interviews, data on legislators' voting records, and secondary sources, Geoffrey Henderson shows that when legislatures are gridlocked on climate policy, environmental groups are more likely to build coalitions to draw upon labor's political resources. In exchange, labor leaders seek certainty that climate policy will redound to union members' benefit, as well as credible commitments from environmental groups to uphold their promises of cooperation. This book offers strategic insights for advocates and demonstrates how the difficulty of enacting reforms in this era of partisan polarization motivates organized groups to cooperate.