The American political climate has become increasingly polarized since the 1970s. Analysis by Keith Poole and Howard Rosenthal shows that voting patterns within Congress have become increasingly divided along party lines, with fewer and fewer moderates. A major cause of polarization appears to be the geographic sorting of voters: Communities and regions of the country have become more politically and ideologically homogeneous, resulting in constituencies in congressional districts and in states that are more strongly conservative or liberal. Whatever its causes, the effects of increased polarization on political discourse and policymaking are clear: There is less room for deliberation between the two parties, and public policy decisionmaking is increasingly driven more by ideology than by objective analysis of which policies, programs, practices, and processes will produce the desired outcomes at the lowest cost. The mission of the RAND Corporation is to provide just this sort of objective analysis, and today's heated political environment presents a serious challenge to this mission. To help make sure that RAND's objective, nonpartisan research influences the policy debate, RAND must work to identify potentially controversial findings and take steps to ensure that they are not misinterpreted or distorted.

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