“I think I’m the right person for the job, but not enough people knew who I was or still know who I am,” Mr. Delaney said in August 2018. “The way to solve that problem, it seems to me, is to get in early and just work harder than everyone else.”

On Friday, he acknowledged that it hadn’t been enough. He said he had concluded that he would not meet the threshold of 15 percent support needed for viability in the caucuses — at least not in enough precincts to matter — but that he could pull enough support to keep other moderate candidates below the threshold, which he did not want to do.

“Particularly these rural counties I went to, I would talk to people in precincts that last time, 2016, 20 people caucused, and I’d be sitting there with two people who I know are going to caucus for me,” he said in an interview on Friday. “I’ve wanted this campaign to be constructive and productive the whole time, and it felt like when I knew that I didn’t have enough support to reach viability in a meaningful way, but I had enough support to pull off from other candidates, I said, well, that’s not very productive.”