For about 15 hours Wednesday night and Thursday morning, Donald Trump was going to endorse Newt Gingrich for the Republican nomination. The news media — or at least several highly respected parts of it — said so.

Except that Trump wasn’t going to do any such thing. On Thursday, the real estate developer and reality TV star threw his support behind Mitt Romney in a news conference at (where else?) a Trump-branded hotel and casino in Las Vegas.

That left plenty of media organizations, including this one, scrambling to correct their earlier reports and pondering how they got this one wrong. Before it was corrected by mid-morning, the ­Trump-endorses-Gingrich line was reported by the Associated Press, the New York Times, the Wall Street Journal, Politico, The Washington Post (in an AP story), and CNN (citing local “affiliates”), as well as local media outlets in Nevada, which holds its Republican caucuses Saturday.

How did they get it wrong? Unlike the premature reports of Joe Paterno’s death last month, which were predicated on a student news organization’s faulty sourcing, the Trump-Gingrich story had what appeared to be a reasonably solid basis. News outlets cited unidentified sources within the Gingrich campaign for the story, standard practice in much political reporting.

In other words, it seems the messengers got some bum messages from a person, or people, who thought they knew more than they did.

“The fact so many different news outlets ‘confirmed’ this [Wednesday] night suggests to me there was more than one mistaken source in the Gingrich campaign and that they were led to believe they would be getting Trump’s endorsement,” New York Times reporter Trip Gabriel wrote in an e-mail. Gabriel was among those who reported the endorsement-that-wasn’t.

The problem, as journalists know, is that a single source can be wrong. Which is why reporters are supposed to turn to additional sources to corroborate what they’ve heard from their first source.

In this case, several news outlets apparently didn’t do that. Gingrich’s spokesman R.C. Hammond had no comment Wednesday night when reporters began querying him about Trump’s intentions. There was also no official comment from Romney’s camp. That should have been a warning sign to do more reporting or steer clear of the story, several reporters said.

“I think some sources thought they knew more than they really did know,” said John Harris, Politico’s editor. “Our reporters, your reporters and other people doing this are smart and work damn hard and they navigate these kinds of things every day. We ask our sources how they know what they know is true. In this case, someone who might ordinarily be in a position to know didn’t know what they were talking about.”

AP’s Washington bureau chief Sally Buzbee said the ­story of Trump endorsing Gingrich “was an accurate account at the time. Clearly, events changed, and our [follow-up story] outlines that in great detail.” AP reported early Thursday that Trump intended to endorse Romney, citing “three Republican officials.”

AP’s follow-up story said “the surprise development comes even though Newt Gingrich had informed close advisers Wednesday night that he had expected to win the real estate developer’s support.”

As in the Paterno fiasco, the rush to report appears also to have been driven, at least in part, by a desire to capture viewers and online visitors. Some news organizations fear they will lose Web site traffic if they are the last to report breaking political news, and higher traffic ultimately can lead to higher advertising revenue.

Reporters and editors at The Post debated whether to run the story early Thursday. Several campaign reporters urged caution, saying they were hearing conflicting accounts from other sources. But those red flags weren’t seen by editors of The Post’s campaign news blog, who posted AP’s original, erroneous story.

Political reporters have gotten plenty wrong before, such as the Chicago Tribune’s famed “Dewey Defeats Truman” headline of 1948. In 1980, the Chicago Sun-Times erroneously told its readers that GOP nominee Ronald Reagan had chosen former president Gerald Ford as his running mate. In 2004, the New York Post wrongly reported that Democratic nominee John Kerry had chosen Rep. Richard Gephardt as his running mate.

Given the speed of reporting in the Twitter age, mistakes tend to get corrected very quickly, said Sree Sreenivasan, a professor of digital journalism at Columbia University. But it also means that erroneous news also travels very, very quickly. “You have to be extra careful now,” he said.

Sreenivasan said the Gingrich mistake is unlikely to be long remembered by the public. “Most journalists try to get things right, and that overrides a single mistake,” he said. “Will people stop paying attention to AP or Politico or the New York Times? I don’t think so. They acknowledged their errors fast. People are grateful for that.”

Observes Politico’s Harris: “I think readers have an expectation that we’ll get it right, and readers have a fair expectation that when we don’t, we take our mistakes seriously. We don’t just laugh it off or roll our eyes or avert our gaze. We have to be candid when we make a mistake.”