Even the Battle for Second Turned Out Well for Trump in Iowa

If there was any question whether Donald J. Trump was on track to win the Republican nomination, it was answered Monday night by the voters of Iowa.

The first-in-the-nation Iowa caucuses delivered him a sweeping victory, offering the most concrete proof yet of his dominance over the Republican Party.

With nearly all the votes counted, Mr. Trump’s share was 51 percent. Ron DeSantis finished a distant second at 21 percent, with Nikki Haley at 19 percent.

The result is not surprising or even unexpected, but Mr. Trump’s victory is no small feat. A year ago, Iowa did not look as if it would be easy for the former president. In an upset eight years ago, Iowa voters rejected Mr. Trump in favor of Ted Cruz. And unlike the rest of the country, the Iowa political establishment has refused to get in line behind Mr. Trump.

Not only did he win in a landslide anyway, but his 30-point margin of victory set a record for a contested Iowa Republican caucus.

Better still for Mr. Trump, neither Mr. DeSantis nor Ms. Haley posted a strong second-place showing that might have bestowed clear momentum for future races. If anything, Mr. DeSantis’s second-place finish might dampen Ms. Haley’s momentum heading into New Hampshire.

Mr. Trump’s decisive victory was built on his usual — if still remarkable — strengths among working-class and rural voters, who made up a preponderance of the Iowa electorate. In county after county across the Iowa countryside, Mr. Trump obtained more than 60 percent of the vote — and sometimes 70 percent — with his rivals languishing in the teens or single digits. He also excelled among white evangelical Christians and self-described “very conservative” voters — two groups that held him back here eight years ago. It’s a