The reality TV star and businessman has spoken extensively about his questions over whether Barak Obama was actually born in Hawaii like he (and the state of Hawaii) says he was.
In 2011, when he was vocally mulling over a possible presidential run, Trump launched a public pursuit of Obama's birth certificate, announcing that he has sent private investigators to Hawaii to see what they could find.
The president then released the long-form version of his birth certificate in response to the uproar that Trump had caused. After its release, Trump said that he was "proud of myself because I've accomplished something nobody has been able to accomplish."
Here is ABC News' report from that day:
Here is more of ABC News' coverage of the issue at the time:
He continued to defend his decision to bring up the issue, and told ABC News’ John Karl in 2013 that he knew what he was doing.
"I don't think I went overboard. Actually, I think it made me very popular... I do think I know what I'm doing," Trump said in 2013.
Trump has not spoken at any events since the Thursday night town hall in New Hampshire, and he was scheduled to appear at a Republican forum this afternoon in South Carolina but his campaign announced that he will not be attending because he "has a significant business transactions that has to close" today.
So far, his campaign has issued a statement that is not a direct condemnation of the man and the points raised.
"The media wants to make this issue about Obama. The bigger issue is that Obama is waging a war against Christians in this country. Christians need support in this country. Their religious liberty is at stake,” a campaign spokesman told ABC News.
In an interview with CNN's Anderson Cooper this June, Trump appeared to try to avoid the topic, but ended up being unable to stop himself from commenting when asked about his 2011 birther push.
When Cooper asked directly if Trump believed Obama was born in the United States, Trump responded "I don't know."
"I really don't know. I mean, I don't know why he wouldn't release his records. But you know, honestly, I don't want to get in it," Trump said.
For his part, Obama has reacted to Trump's continued interest in the topic with a mix of frustration (at the press conference when he released the long-form birth certificate) and humor (on late night shows and at the White House Correspondents’ Dinner).
During a 2011 appearance on the Tonight Show, Obama continued to laugh it off.
"This all dates back to when we were growing up together in Kenya," Obama joked.
"We had constant run-ins on the soccer field, you know he wasn’t very good and resented it. When we finally moved to America, I thought it would be over," he said.