MIAMI—Donald Trump has advanced to the brink of the Republican presidential nomination not by transforming the GOP electorate, but by dividing it along a new axis.
Though some conservative Trump critics have claimed that he has relied on a surge of non-Republican voters, the exit polls conducted so far in 15 states point toward the opposite conclusion. Overall, although turnout has soared from 2012, the share of the total primary votes cast by self-identified Republicans this year is virtually unchanged. And Trump has beaten his rivals among self-identified Republicans in every exit poll conducted in states that he has won.
Together these patterns suggest that Trump has built his coalition primarily from voters within the heart of the Republican electorate—a dynamic that could make it more difficult for the party leaders to deny him the nomination if he finishes the primaries with the most delegates, but less than an absolute majority. It also suggests that his rise could signal a lasting shift in the party’s balance of power toward the anti-establishment, heavily blue-collar voters who have provided the core of his support.
Trump’s consistent success with those voters has replaced many of the party’s traditional divides—such as religious identification and ideology—with a new fissure centered on class and alienation from institutions. In that sense, Trump this year has been as much a demand-side as a supply-side phenomenon. He is coalescing, and giving voice to, an increasingly important component of the existing Republican coalition—one that earlier blue-collar populists such as Patrick J. Buchanan in 1996 and Rick Santorum in 2012 also tried to mobilize, with much less success.