Most stay with their party, but some leave and return, while others 'defect' % who identified with/leaned toward a party in December 2015 who as of March 2017 Note: Refusals not shown, Mar. 2017,
But over a 15-month period encompassing the 2016 presidential campaign, about 10% of Republicans and Democrats “defected” from their parties to the opposing party.
The numbers are very similar among those who were Democrats in 2015: 79% consistently identified as Democrats or leaned Democratic in all five surveys, while 9% switched parties at some point but came back to the Democratic Party by March.
Most stay with their party, but some leave and return,  | while others 'defect'  | % who identified with/leaned toward a party in December 2015  | who as of March 2017  | Consistently identified with  | Identified for leaned  | or leaned toward same party Returned toward other party  | Rep/ Lean Rep  | 78  | in Dec. 15  | Dem/Lean Dem  | 79  | 10  | in Dec. 15  | Note: Refusals not shown,  | Source: Five American Trends Panel surveys conducted Dec. 2015 through  | Mar. 2017,  | PEW RESEARCH CENTER 