WASHINGTON — The Mueller report, long thought by Democrats to be the key to ousting President Donald Trump, may instead become a powerful tool for his re-election campaign.

After 22 months, special counsel Robert Mueller reported he found no evidence of anyone on the 2016 Trump campaign conspiring with the Russian government to throw that election, and Attorney General William Barr said he didn't see sufficient evidence to prosecute the president for obstruction of justice.

Or, in Trump-speak: 'NO COLLUSION!'

A defiant Trump described the investigation Sunday as "an illegal takedown that failed" and called for an inquiry into "the other side" — the government officials and Democrats who pursued the line that his campaign might have coordinated with Moscow.

Trump will continue to make the case to the American voting public — with the Mueller investigation as Exhibit A — that he was target of a partisan "witch hunt" designed to hamstring his administration and reverse the results of the 2016 election.

"Democrats took us on a frantic, chaotic, conspiracy-laden roller coaster for two years, alleging wrongdoing where there was none," Trump campaign manager Brad Parscale said in a statement. "So distraught and blindsided by the results of the 2016 elections, Democrats lied to the American people continually, hoping to undo the legitimate election of President Trump."

Trump and his team may be vastly oversimplifying Mueller's full conclusions, which have not been revealed and could include damaging information about the president's behavior. But even if there are land mines in that report — and if it even sees the light of day — many voters may skip the nuance and determine that Trump did nothing wrong if he wasn't prosecuted.

The summary findings Barr sent to Congress on Sunday make it easier for Trump to sell the report as a full exoneration (which it explicitly was not) and himself as a casualty of partisan warfare. That's true even though he and his allies argued Hillary Clinton was still guilty of crimes after the Justice Department decision not to prosecute her over three years ago her use of private email.

"The Democrats have done something that I never thought was possible: They’ve actually turned Donald Trump into a victim," said Matt Schlapp, chairman of the American Conservative Union and a frequent defender of the president on cable television, in a telephone interview.

"Any other Republican would have withered under this pressure, and under this media coverage, and the president is genetically predetermined to know how to fight and he fought hard," Schlapp said. "It endears him to the people who voted for him in 2016" not knowing whether they were more in favor of him or against rival Hillary Clinton.

But even absent a foil in Democrats, the findings unburden Trump from a probe that has cast a dark shadow over virtually his entire presidency. That's a major boon as he turns the corner to his re-election effort.

"This was a distraction for two years and the president was able to accomplish an ambitious agenda," Republican National Committee co-chair Tommy Hicks Jr. said in a text exchange with NBC. "The American people will have an opportunity to vote on his track record, which speaks for itself."

Of course, the public fight over Trump's conduct isn't over.

Barr's letter to lawmakers Sunday revealed that Mueller himself had not made a determination on the question of whether the president had obstructed justice.

"While this report does not conclude that the President committed a crime, it also does not exonerate him," Mueller wrote, according to Barr. It was Barr, in consultation with Deputy Attorney General Rod Rosenstein, who determined that there was not sufficient evidence to establish that Trump had obstructed justice.

Without seeing what Mueller found — the facts and arguments for and against obstruction in an underlying report that remains in Barr's hands — it's impossible to know what the veteran prosecutor thought.

If the report is made public, the tricky part for Trump's Democratic rivals will become taking whatever Mueller found in his review of possible obstruction of justice and making the argument that it is enough for voters to conclude he is not fit for re-election. Or, they may decide they would rather fight him on other fronts entirely.

Congressional Democrats, who are pursuing several other lines of inquiry into various Trump activities, immediately renewed their calls for the full Mueller report to be released publicly. In addition, federal and New York state prosecutors are conducting inquiries that could touch on the president.

In a joint statement, Speaker Nancy Pelosi, D-Calif., and Senate Minority Leader Chuck Schumer, D-N.Y., challenged Barr's findings and, because he had criticized the investigation before being appointed to his job, his impartiality.

"The fact that Special Counsel Mueller’s report does not exonerate the president on a charge as serious as obstruction of justice demonstrates how urgent it is that the full report and underlying documentation be made public without any further delay," they said. "Given Mr. Barr’s public record of bias against the Special Counsel’s inquiry, he is not a neutral observer and is not in a position to make objective determinations about the report."

But for the most part, Democrats were very quiet publicly in the wake of Barr's letter while Republicans took victory laps.

The Trump re-election campaign released a video called "COLLUSION HOAX!" and immediately began asking donors to give in response to the news.

James Comey, the FBI director whose firing by Trump precipitated Mueller's appointment, appeared confused by the conclusions. He tweeted a picture of himself standing among very tall trees with the cryptic message: "So many questions."

For Team Trump, there was just one answer: victory.

White House counselor Kellyanne Conway, who served as campaign manager on Trump's 2016 campaign, tweeted a congratulatory note to her boss.

"Today you won the 2016 election all over again," she wrote. "And got a gift for the 2020 election. They’ll never get you because they’ll never 'get' you."