Washington (CNN) Deflated, frustrated, apprehensive -- with the acquittal of President Donald Trump , diplomats and officials who provided testimony about the administration's dealings with Ukraine are bracing for the fallout now that the impeachment trial has concluded. Some of them are angry at former administration officials, including John Bolton, who failed to come forward and many are worried about what comes next.

"All the carnage for something that doesn't mean very much," explained one of the officials who provided public testimony about Trump's effort to leverage military aid for personal political gain. "Our domestic political battles have just trampled over what our national interests are."

The official was not alone in expressing frustration that partisan politics dictated Trump's acquittal on Wednesday.

Officials including former ambassador to Ukraine Marie Yovanovitch, White House Ukraine expert Alexander Vindman and Bill Taylor, who took over as the top diplomat in Kiev, were thrust into the spotlight and endured a barrage of criticism from Trump allies after they testified.

CNN spoke to about half the total of 17 witnesses about their reactions as the historic drama of the nation's third impeachment trial come to an end. Despite many of them having provided public testimony, they did not want to be named in this article in an effort to avoid attention that they fear could undermine their return to diplomacy.

Many witnesses worried about a presidential vendetta against the bureaucracy that Trump sees as a "Deep State" conspiring against him. Three of them contrasted their decision to provide testimony to officials like former national security adviser John Bolton, who has monetized a national crisis, parlaying critical insider knowledge about the President's dealings into a multi-million-dollar book deal even as he avoided testifying publicly. And many described their frustration with a dysfunctional Congress.

"Republicans think Democrats are a threat to the nation, and the Democrats think the Republicans are a threat to the nation," a second official who provided testimony explained. "Right now, we think the threat that we face is each other."

Multiple sources voiced their frustration at both sides of the aisle -- wishing that the Democrats had developed a stronger case and that Republicans had more seriously looked at the actions Trump had taken.

None of the witnesses CNN spoke to said they had any regrets about providing testimony -- they saw it as their duty to do so.

Yovanovitch echoed that sentiment in a Washington Post op-ed published Thursday, the day after Trump was acquitted, writing that the diplomats and officials who provided testimony did so because it is the "American way to speak up about wrongdoing." Yovanovitch said she has been subject to a "storm of criticism, lies and malicious conspiracies."

Anger at Bolton

That sense of responsibility may drive the public servants' anger at Bolton.

Trump's former national security adviser is seen as a key witness who could shed light on the President's decision to put a hold on security assistance to Ukraine. According to a draft manuscript of Bolton's book obtained by The New York Times, Bolton writes that Trump ordered him to help with the pressure campaign to push Ukraine dig up dirt on Trump's Democratic rivals.

But Bolton, who is seeking to remain a player in the Republican foreign policy space, according to those familiar with his future plans, has avoided becoming a star witness. He refused to testify before the Democrat-controlled House inquiry, saying the White House hadn't authorized him to appear. He then said that if subpoenaed, he would come before the Republican-controlled Senate, which voted against hearing from witnesses.

Bolton's dance around testifying ahead of his book being published later this year has earned him ferocious criticism.

The second official noted that Bolton has been dangling the fact that he knows details about Trump's actions that have not yet been revealed. Bolton is "trying to have it both ways," that official said.

For some career officials who testified, the former national security adviser's coy behavior during one of most consequential moments in American history has cemented their belief that they did the right thing in detailing what they knew to Congress. But they are still angry that Bolton -- despite reportedly expressing support for those who provided testimony at a closed-door event last week -- will walk away having had no direct participation in the entire impeachment.

"Great. So our lives are ruined, our names dragged through the mud, but [Bolton] gets to wash his hands of it," said a third official who testified.

The witnesses expressed a similar disappointment in lawmakers, who will return to their partisan corners now that the trial is over.

Many of the diplomats who provided testimony feel distressed by the strong undercurrent politics has played in the entire process and fear that it may have an outsized impact on the future of their careers.

They are no longer anonymous diplomats. For professionals trained to be apolitical, viewing their future through a political lens goes against the grain of everything they have been taught.

"It is now a part of my identity," the first official told CNN. "I worry about that."

A fourth official who testified said that they are keeping the longer-term in mind.

"I think it will be fine over the long term," this person said. "I think - and hope - that future leadership will understand that we were just doing our jobs and trying our best to uphold our oath to the Constitution."

A fifth official said that they are "looking forward to all this being over." This source expressed some apprehension over losing "anonymity" because of the public portion of the inquiry and said that has been a difficult adjustment in recent weeks.

Careers derailed

Diplomats' careers have already been derailed in the wake of the Ukraine investigation.

Yovanovitch, who was forced out at Trump's direction, retired last week . She was the fourth State Department official whose departure was tied to the impeachment -- following former US Special Representative to Ukraine Kurt Volker, former Pompeo adviser Michael McKinley and Ambassador Bill Taylor.

In recent weeks Taylor and Volker have written op-eds. Both of them argued the US should maintain support for Ukraine in the face of continue Russian aggression. There is no current US ambassador to Ukraine or a top State Department official in Washington who has assumed the portfolio.

Concern about the proceedings and what may come in their aftermath have permeated the State Department, extending even to staff who didn't play a role in the impeachment hearings.

During the trial, office TVs were tuned in to the Senate proceedings throughout America's oldest Cabinet agency. Though some State employees said they had no concerns about monitoring the proceedings, others told CNN that they were watching with caution, focused on keeping their head down, worried about political retribution.

For the time being, the officials who testified have not faced backlash, apart from criticism from Trump. They largely have been praised by colleagues. They have gotten pats on the back in the State Department elevators from people they had never met, and notes from former ambassadors commending their integrity.

As they get further from the spotlight, however, fear looms.

"It would be bad politics for Trump to be seen as going after mid-level folks. And it would take effort," said the second diplomat who testified. Referring to Secretary of State Mike Pompeo , who has been criticized for failing to defend department employees from the President's attacks, the diplomat said they didn't "think people in State, including Pompeo, want to go after us."

But then this official added a caveat about the President, who is known to nurse resentments and have a long memory for perceived slights. "If he is reelected, he will feel emboldened," the diplomat said, "and this is where he could go after what he deemed the 'Deep State.'"

This story was updated Thursday with additional details.