A few years ago, I asked Gary Jacobson for permission to reprint a chart measuring party polarization by using the president’s approval rating by those in the president’s party minus the president’s approval rating by those in the other party.  The last time I saw it was during the second George W. Bush administration, and the gap was at record highs.(The dip you see under Bush is 9/11.)

Gary has now updated the data, and with his permission I am reposting it below.  Although the numbers are slightly off the highs of the second Bush administration, they are still at near high levels.