Despite a mountain of evidence supplied by cooperative diplomats — and a public admission and hasty retraction by acting White House chief of staff Mick Mulvaney — the uncertainty surrounding the hold on the aid has only deepened over time, according to interview transcripts released this week as part of the impeachment inquiry.

In fact, what has become increasingly clear is that only a small cadre of budget officials — and Trump himself — has the answers. And they have fought harder than anyone to spurn Democrats’ demands for testimony.

“We’re looking for ways to fill that in,” said Rep. Jamie Raskin (D-Md.), a member of the House Oversight and Reform Committee. “But if their refusal to testify keeps us from totally filling in the picture, we will fill it in with adverse inferences against the people who are refusing to testify.”

“The overwhelming weight of evidence we have received tells us the president ordered that aid to be held up,” Raskin added. “However, the president has succeeded in obstructing the witnesses who would tell us the exact mechanics.”

If Democrats intend to make a public case that Trump attempted to shake down his Ukrainian counterpart, they will face pressure to address how the outright stonewall by Trump’s budget officials has impeded their effort to solve this mystery.

Democrats have named Russell Vought, the acting director of the White House Office of Management and Budget, and Michael Duffey, OMB’s national security chief, as crucial figures in their quest to learn how and why the aid was put on ice. Both were subpoenaed; but neither showed up, and several subordinates blew off the inquiry as well.

“OMB officials … will not be complying with deposition requests,” Vought tweeted on Oct. 21, dubbing the impeachment inquiry a “sham process.”

It’s possible that witness transcripts expected to be released in the coming days will shed more light on the missing link — particularly the testimony of Timothy Morrison, a top National Security Council official whom diplomats said was their highest-level contact in trying to pry loose the frozen aid.

But so far, the mystery remains — and it comes as Democrats begin public impeachment hearings next week.

The saga began on July 18, when OMB revealed to senior administration officials that Trump, through Mulvaney and Vought’s office, had frozen a package of congressionally mandated military assistance to Ukraine intended to fend off Russian aggression.

Though officials at the highest levels of the Trump administration were aghast at the move, it was kept under wraps until POLITICO revealed the details on Aug. 28. Two weeks later, amid withering pressure from inside and outside his administration, Trump relented.

In the absence of cooperation from OMB, impeachment investigators have so far been unable to showcase evidence directly linking Trump’s hold on aid and his demand that Ukraine investigate former Vice President Joe Biden and other Democrats.

Instead, lawmakers have been told a tale of mass confusion and frustration across nearly every facet of government from a raft of senior State Department and Pentagon officials. Some witnesses said they had presumed or heard there was a quid pro quo involving military aid, but could not verify that that was the case.

“I was embarrassed that I could not give [Ukraine] any explanation for why it was withheld,” William Taylor, the top U.S. diplomat in Ukraine, told investigators.

Lt. Col. Alexander Vindman, who handles Ukraine issues for the National Security Council, testified that he learned of the hold on aid earlier that month, on July 3. He, too, never received a clear explanation other than an assumption that the hold was placed “to make sure that the assistance continues to align with the administration priorities.”

Democrats have repeatedly stated that the outright blockade by Mulvaney and budget officials will be used as evidence of obstruction of Congress by Trump, and it will almost certainly comprise an article of impeachment.

But what Democrats have learned is that officials at the highest levels of the White House’s national security apparatus and the State Department were completely baffled. They all wanted the aid released to Ukraine, but they could not get an explanation for why it was blocked.

Even Gordon Sondland, Trump’s closest ally in the diplomatic corps, testified that to this day, he never understood the reason Trump ordered the hold, even though he asked the president directly.

“I always believed that suspending aid to Ukraine was ill-advised, although I did not know (and still do not know) when, why, or by whom the aid was suspended,” Sondland, the U.S. ambassador to the European Union, told investigators before saying he presumed the freeze was connected to Trump’s demand for investigations.

It was George Kent, a senior State Department official overseeing the region that includes Ukraine, who provided the most vivid account yet of the chaos unleashed when he and other officials learned of the hold on aid.

Kent told investigators that OMB, on a July 18 video call, informed the State Department and other agencies that Mulvaney had ordered the hold at the direction of the president.

“There was great confusion among the rest of us because we didn't understand why that had happened,” Kent told lawmakers. The OMB official who delivered the message, Kent said, apologized because he did not have an explanation.

“Since there was unanimity that this was in our national interest, it just surprised all of us,” Kent added.

That meeting triggered a follow-up of more senior officials on July 23. Yet again, there was unanimity that the aid should be released — and no understanding of what motivated OMB’s hold. Kent described “broad support” across the State Department, Pentagon and both parties in Congress.

At that meeting, Kent said, Pentagon official Laura Cooper raised concerns that if the hold stretched past Aug. 6, they might be unable to provide all of the funds to Ukraine before a Sept. 30 fiscal year deadline wiped it out. Other officials raised questions, Kent said, about whether OMB even had the legal standing to block the aid. Cooper testified to impeachment investigators last month, but the transcript of her deposition has yet to be released.

At a July 26 meeting, the highest-level officials yet — those just below Secretary of State Mike Pompeo, Defense Secretary Mark Esper and then-national security adviser John Bolton — once again pushed for the release of the aid.

But there was one exception, Kent said: OMB.

That’s when concern began to grow outside the Trump administration. Kent told investigators that Republican lawmakers — including Senate Armed Services Committee Chairman James Inhofe and Sen. Rob Portman, a former OMB chief — called the president directly to inquire about the aid freeze. Senate Majority Leader Mitch McConnell has said publicly that he called around to Pompeo and Esper about the military aid as well.

Some of the president’s defenders have asserted that holds on foreign aid are fairly common — but Fiona Hill, a former Russia adviser on the National Security Council, told investigators that this particular hold was unusual, especially because there was no explanation or justification, and all of the factors that would typically lead to a hold had been resolved.

Finally, on Sept. 11, after news of the hold had been public for two weeks, it was lifted, and the flow of aid resumed.

Most vexingly for Democrats, the witnesses who could shed light on this gap in the narrative have clung most closely to Trump’s order that administration officials refuse to cooperate.

Mulvaney, who delivered Trump’s order to the White House budget office, defied a congressional subpoena Friday and refused to appear for a deposition. Before Mulvaney, at least four White House budget officials refused to testify.

Democrats have been left with vivid but uncertain accounts from diplomats who battled their superiors to get the aid released and commiserated with colleagues in the Pentagon about why no one explained to them what was going on.

Mulvaney finally appeared to offer some clarity when, during an Oct. 17 news conference, he said the aid freeze was connected to Trump’s call on Ukraine to launch politically motivated investigations.

“Get over it,” he said from a White House podium, when asked if Trump had engaged in a quid pro quo. Hours later, however, he issued a statement retracting his remarks.

Now, Democrats still do not have a single witness on record about what the White House decision-makers told their colleagues about what was happening to the money and why.

Sarah Ferris contributed to this report.

