Ideology and Independents
Only 25 percent of Republican Party primary voters labels themselves “moderate” (the so-called “lane” Bush, Kasich, Christie and many others were competing in). Clinton draws from 39 percent of Democrats who are moderates. (But the liberal wing is growing and moderates contracting 52% in 2008 to 39% today.)
Sanders does better with independents, but that represents only a quarters of Democratic primary voters, whereas 32 percent of Republicans are independent and many of them have favored Donald Trump.
Gender, Age and Race
More than half of the Democratic voters (57%) are women, the group Clinton dominates against Sanders. Less than half of Republican voters (49%) are women.
The demographic Sanders is helped with are voters under the age of 30 years old. Seventeen percent of Democratic primary voters have been young, many specifically drawn to Sanders. Only 11 percent of Republican voters are less than thirty.
Clinton’s near monopoly of non-White voters has been a major asset, and they represent 39 percent of the Democratic primary electorate vs. only 10 percent among Republican primary voters. Both younger and non-White voters are a growing demographic of the Democratic Party’s primary electorate.