It's not just your imagination or the wild claims of media: political partisanship is indeed growing. Annual polling by the Pew Research Center showed how partisan polarization rose sharply in the past several years:
As Americans head to the polls this November, their values and basic beliefs are more polarized along partisan lines than at any point in the past 25 years. Unlike in 1987, when this series of surveys began, the values gap between Republicans and Democrats is now greater than gender, age, race or class divides.
Overall, there has been much more stability than change across the 48 political values measures that the Pew Research Center has tracked since 1987. But the average partisan gap has nearly doubled over this 25-year period – from 10 percentage points in 1987 to 18 percentage points in the new study.
Nearly all of the increases have occurred during the presidencies of George W. Bush and Barack Obama. During this period, both parties’ bases have often been critical of their parties for not standing up for their traditional positions.