How did Trump do in 2016?
Although Trump emerged as the Republican nominee in 2016, he got off to a slow start in Iowa. In that year’s caucuses, Trump narrowly came in second behind Texas Sen. Ted Cruz, receiving 24.3 percent of the vote compared to Cruz’s 27.6 percent, while Florida Sen. Marco Rubio finished in a close third with 23.1 percent. The crowded candidate field and highly-competitive contest produced a messy map, with Cruz and Trump tending to do better in places with fewer four-year college graduates — often more rural areas — and Rubio doing comparably better in the state’s more well-educated population centers.
It was a competitive start to a primary that was fraught with uncertainty from the jump. While competitive primaries aren't unheard of, in the modern presidential primary era (which starts after the reforms that stemmed from the 1968 election), party elites and insiders have been largely successful at putting their thumb on the scale, a political science theory known as "the party decides." In brief, the theory holds that the preferences of party elites, rather than those of rank-and-file primary voters, are decisive in determining the party's nominee. More specifically, party elites have already exerted their influence through endorsements to effectively anoint a nominee by the time voting contests even begin.
The 2016 GOP primary represented a break from that trend, though, because Republican elected officials were slow to endorse a candidate, which some characterized as the party failing to decide. Ahead of the Iowa caucuses, Trump had received zero endorsements from sitting members of Congress or governors, but Cruz, Rubio and the other contenders weren't raking them in, either — and in that vacuum, Trump was able to build momentum. In this context, Iowa's close result seemed to be a microcosm of that high level of uncertainty.
While Iowa's results seemed to throw cold water on Trump's early momentum, he may not have been the most intuitive candidate given the state's demographics. It's largely known that Iowans take their winnowing role in the primary process seriously, but the state's primary hasn't picked the eventual Republican nominee since 2000. More reliably, Iowans since then have picked the candidate most closely associated with the religious right (like Rick Santorum in 2012, and Mike Huckabee in 2008), because evangelical voters are a strong voting bloc there. In 2016, that bloc was decidedly behind Cruz.
This time, despite concerted efforts by DeSantis to court evangelical voters, Trump won't have that issue. The evangelical vote in Iowa, and beyond, is now fully in Trump's corner. And with the party establishment also seemingly lining up behind him, it's no wonder he's seen as an overwhelming front-runner this evening.