Here’s a good way to tell: If Trump’s supporters are fueling the rise, he should be performing best in places with the biggest increases in turnout. We divvied up the states that voted in both 2008 and 2016 (which are comparable because they included contested primaries for both parties) into three groups — those with huge increases in vote totals (85 percent or more compared with 2008), those with moderate increases (33 percent to 84 percent) and those with increases below 32 percent or decreases.

The data show Trump’s support didn’t peak in high-turnout states. Among those states with the largest turnout increases compared with 2008 — 85 percent or more — Trump garnered 34.3 percent of the vote, lower than his average overall (34.9 percent). He performed slightly better in states with a moderate turnout increase, and worse in states where turnout did not rise as much. The comparison does not differ much when looking at 2012 turnout data; Trump won 32.9 percent in states that had the largest turnout increases, which is below his cross-state average.