Donald Trump speaks to supporters on the Drake University campus at a fundraiser on Jan. 28, 2016, to benefit veterans after skipping the Fox News GOP debate in Des Moines that night. (Larry W. Smith/European Pressphoto Agency)

One night in January, Donald Trump skipped a GOP debate and instead held his own televised fundraiser for veterans. At the end of the night, Trump proclaimed it a huge success: “We just cracked $6 million, right? Six million.”

Now, Trump’s campaign says that number is incorrect.

Campaign manager Corey Lewandowski said the fundraiser actually netted about $4.5 million, or 75 percent of the total that Trump announced.

Lewandowski blamed the shortfall on Trump’s own wealthy acquaintances. He said some of them had promised big donations that Trump was counting on when he said he had raised $6 million. But Lewandowski said those donors backed out and gave nothing.

“There were some individuals who he’d spoken to, who were going to write large checks, [who] for whatever reason . . . didn’t do it,” Lewandowski said in a telephone interview. “I can’t tell you who.”

An Army veteran’s helmet and boots are seen on a motorcycle near a line of supporters waiting to attend a Trump campaign rally in Wilkes-Barre, Pa., on April 25. (Mel Evans/AP)

Lewandowski also said he did not know whether a $1 million pledge from Trump himself was counted as part of the $4.5 million total. He said Trump has given that amount, but he declined to identify any recipients.

[Trump once revealed his income tax returns. They showed he didn’t pay a cent.]

The comments appear to be the first acknowledgment — almost four months later — that Trump’s fundraiser had brought in less than the candidate said. Lewandowski said he did not know the exact total raised or how much of it remained unspent.

Even with the lower total, Trump’s fundraiser brought in millions of dollars for veterans’ charities. The Washington Post’s accounting, based on interviews with charities, has found at least $3.1 million in donations to veterans groups.

Trump’s fundraiser Jan. 28 was an indelible moment, a one-night showcase of the GOP front-runner’s boldness and charm.

In a single evening in Des Moines, Trump showed Fox News — the host of that night’s Trump-less debate — that he was powerful enough to spurn the Fox network.

At the same time, he showed a national audience that he could conjure a multimillion-dollar benefit out of nothing, using connections, showmanship and his own wealth.

“Donald Trump — another great builder in New York, now a politician — I can’t stand this, a politician,” Trump said, in his trademark run-on style, after he’d listed a series of gifts from other wealthy friends. “I don’t want to be called a politician. All talk, no action — I refuse to be called a politician. Donald Trump gave $1 million. Okay?”

In the days after the fundraiser, Trump repeated the $6 million figure in TV appearances and at Iowa rallies. “At that rally we raised, in one hour, $6 million. Is that good?” Trump said four days afterward at a rally in Cedar Rapids, Iowa.

At first, he was very public about giving the money away. In rallies across Iowa, Trump would call representatives of local veterans groups up to the stage and present them with oversize checks.

In some cases, the money came from friends of Trump’s who sent checks directly to veterans groups. In other cases, the money was routed through Trump’s personal foundation.

For the groups that received this money — often dealing with aging veterans from the Vietnam War, along with returning troops from Iraq and Afghanistan — the money was an enormous help.

“It’s all long gone,” said James Kallstrom, a retired FBI official who is the chairman of the Marine Corps-Law Enforcement Foundation. In March, his group received $100,000, which Kallstrom said would go toward $30,000 educational grants for the children of Marines killed on active duty. “I believe there was a helicopter crash that had, oh God, I forget how many there were. . . . They’re all young, and they all have young children.”

But, as the race continued, the checks from the fundraiser began to come less frequently. The most recent check identified by The Post was dated March 25.

In recent weeks, Trump and his campaign repeatedly declined to give new details about how much they have given away.

“Why should I give you records?” Trump said in an interview with The Post this month. “I don’t have to give you records.”

Paul Rieckhoff, founder of Iraq and Afghanistan Veterans of America, said Trump’s refusal to divulge how much of the money he had distributed raised questions about whether the candidate intended the fundraiser primarily as a public-relations effort for himself.

“That’s just shady. Right? No matter how you cut it, that’s just shady,” Rieckhoff said. “If he was going to make it right, a couple of weeks before Memorial Day would be a good time to do it. It behooves him, not just politically but ethically, to come forward and account for this money.”

Trump provided no official way for charities to apply for the money. Groups around the country still tried, sending letters and hitting up local veterans-for-Trump leaders.

“We haven’t heard anything,” said Judy Schaffer of Heroes to Heroes, a New Jersey-based group that sends veterans on nondenominational trips to Israel to prevent suicide and promote “spiritual healing.” Her group had received a donation from Trump’s personal foundation years before.

“We have a waiting list of over 200 veterans. Many of them have already attempted suicide,” Schaffer said this week. “And it keeps me up at night, not being able to send more people.”

Lewandowski said Trump has decided on about two dozen groups that will get the remainder of the money in the next couple of weeks. He said the groups have been vetted and had been chosen by word of mouth within the Trump campaign or from causes Trump had previously supported.

Lewandowski said Trump should not be faulted for promising $6 million in donations.

“What he said was, ‘We hope to get $6 million.’ He said this at an event where we were trying to get money. It was a best guess,” Lewandowski said. “That was his goal. His goal was to get somewhere around $6 million.”

On the night of the fundraiser, Trump named nine big donors, including himself.

Since then, The Post has found evidence from Trump’s staff, from the donors or from veterans charities that received money that seven of those nine gave money as promised. Those gifts added up to $3.78 million.

On top of that, Trump said small-dollar donors gave $670,000 over the Internet. That adds up to $4.45 million.

So, were those other two big donors among the ones who backed out?

One of them was a shopping-mall magnate from Ohio who did not respond to multiple calls, emails and messages from The Post seeking to confirm his donations. But even if that man did back out, his pledge was so small — $50,000 — that it would make little difference in a tally of millions.

The other donor had made a much bigger promise: Trump, with his vow to give $1 million.

In the past few days, The Post has interviewed 22 veterans charities that received donations as a result of Trump’s fundraiser. None of them have reported receiving personal donations from Trump.

Did Trump make good on his promise to give from his personal funds?

“The money is fully spent. Mr. Trump’s money is fully spent,” Lewandowski said.

To whom did Trump give, and in what amounts?

“He’s not going to share that information,” Lewandowski said.