In the 2016 presidential campaign, the first cut has indeed been the deepest.
An examination of the 22 state exit polls conducted so far by a consortium of media organizations indicates that the patterns of voter allegiance that emerged during the very first contests in February have largely persisted since. That’s been true even as the race has crossed through different regions of the country, and the Republican field has dramatically winnowed.
On both sides, the leading candidates have established clear patterns of support—and have faced largely intractable pockets of resistance. For the most part, demography has trumped geography, with the big exception that in the Democratic race challenger Bernie Sanders has run much better against front-runner Hillary Clinton among several groups of voters outside of the South than in Dixie, including whites, the middle-aged, and those who describe themselves as very liberal.
On the Democratic side, the unexpectedly competitive Clinton/Sanders contest has split the party along strikingly consistent lines of age, race, gender, partisan affiliation, and ideology.
Sanders’s dominance among young voters has been almost complete: He has carried those younger than 30 in 20 of the 22 states with exit polls, faltering only in Alabama and Mississippi. Though it hasn’t received as much notice, Clinton has been equally dominant among older voters. She’s carried seniors 65 and older in every state with an exit poll except Vermont. And she’s won those aged 45-64 in 20 of the 22 states, losing them just in Vermont and New Hampshire. Measured by age, the most deeply divided group is those between age 30-44, who have mostly voted along geographical lines. They voted for Clinton in 12 states, all in the South, except for New York and Massachusetts; and voted for Sanders in 10 states, all of them outside the South.