According to Pew Research, there’s a widening gap between Republicans and Democrats on the issue of evolution:
In 2009, 54% of Republicans and 64% of Democrats said humans have evolved over time, a difference of 10 percentage points. Today, 43% of Republicans and 67% of Democrats say humans have evolved, a 24-point gap.
Pew says that there are no similar shifts in other demographics. Racially and religiously we’re pretty much where we were five years ago. That suggests that people who find the evidence for evolution compelling are leaving the Republican party.
This supports the common wisdom that the Republican Party is has a brand problem, and moderates no longer wish to be associated with the party.