A House Divided Polarization and Its Effect on RAND 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 pro