Some studies have used DW-Nominate scores to blame Republicans for congressional polarization. At The Washington Post, L.J. Zigerell writes:
However, this pattern of asymmetric polarization is not present in other estimates of ideology. Data from Adam Bonica‘s CFscores (“campaign finance” scores), which provide ideology estimates for members of congress based on donations to and from each member, indicate that since 1980 congressional Democrats have moved left slightly more than congressional Republicans have moved right...
And estimates developed by Michael Bailey also do not show that Republicans have polarized more than Democrats.
