WASHINGTON (Reuters) - Former Special Counsel Robert Mueller emphasized on Wednesday he had not exonerated Donald Trump of obstruction of justice, as the president has claimed, but his long-awaited congressional testimony did little to add momentum to any Democratic impeachment ambitions and Trump heartily declared victory.

In seven hours of congressional testimony, Mueller accused Trump of not always being truthful, called his support for the 2016 release of stolen Democratic emails “problematic” and said Russia would again try to interfere in the 2020 U.S. elections.

“They are doing it while we sit here. And they expect to do it in our next election,” Mueller told lawmakers in back-to-back hearings on his inquiry into Russian interference in the 2016 U.S. election to boost Republican Trump’s candidacy.

Despite Mueller’s assertion that Trump could be indicted after leaving office, the president was triumphant after the former FBI director’s appearances before the Democratic-controlled House of Representatives Judiciary and Intelligence committees.

“This was a very big day for the Republican Party. And you could say this was a great day for me, but I don’t even like to say that,” Trump said after Mueller’s lengthy and at times halting testimony during which he sometimes could not hear questions and had to correct at least one answer

During a day of high-stakes political theater, Mueller, 74, answered questions publicly for the first time on his investigation, with Democrats and Republicans taking familiar positions at a time of deep U.S. partisan divisions.

The marathon televised hearings apparently left Democrats who control the House no closer to launching the impeachment process to try to remove the president even as he seeks re-election in 2020.

Mueller, for his part, refused to discuss the “impeachment issue.”

‘DEMOCRATS HAD NOTHING’ -TRUMP

“The Democrats had nothing,” Trump told reporters outside the White House as he was leaving on a trip to West Virginia. “And now they have less than nothing. And I think they’re going to lose the 2020 election very big, including congressional seats, because of the path that they choose.”

Democrats said they would go to court this week to enforce a subpoena of former White House counsel Don McGahn and to ask for grand jury material related to Mueller’s probe.

House Speaker Nancy Pelosi gave no sign she was speeding up her step-by-step approach to considering impeachment, saying: “We want to have the strongest possible case, to make a decision as to what path we will go down.”

Mueller spent 22 months investigating what he concluded was Russian interference in a “sweeping and systematic fashion” in the 2016 U.S. election to help Trump as well as the president’s actions to impede the inquiry.

Mueller defended the inquiry’s integrity under repeated attack by Trump’s conservative Republican allies. The president lauded those lawmakers as “incredible warriors.”

Democrats who wanted Mueller to bolster their case for impeachment or provide game-changing testimony about the president, and Republicans who wanted to show that the investigation was a politically motivated hit job on Trump engineered by his enemies, may have come away frustrated.

Mueller, a reluctant witness who appeared only after being subpoenaed, often gave terse responses like “I can’t speak to that,” “I’m not going to get into that,” and “It is beyond my purview,” or merely referred lawmakers to the text of his 448-page investigative report.

The Judiciary Committee’s Democratic chairman, Jerrold Nadler, said Mueller had endured “repeated and grossly unfair personal attacks” and that no one, including Trump, was “above the law.” The Intelligence Committee’s Democratic chairman, Adam Schiff, accused Trump’s 2016 campaign of “disloyalty to country” for inviting, encouraging and making full use of Russian election meddling.

Republican lawmakers tried to paint Mueller’s investigation as unfair to the president, with Louie Gohmert telling the decorated Vietnam War veteran and longtime federal prosecutor: “You perpetuated injustice,” and Guy Reschenthaler calling the manner in which the inquiry was conducted “un-American.”

“Welcome, everyone, to the last gasp of the Russian collusion conspiracy theory,” said Devin Nunes, the Intelligence Committee’s top Republican.

Mueller’s report, released in redacted form on April 18, did not reach a conclusion on whether Trump committed the crime of obstruction of justice with his actions aimed at undermining the inquiry, but did not exonerate him. The report also said the inquiry found insufficient evidence to establish that Trump and his campaign had engaged in a criminal conspiracy with Russia.

Trump has said the Mueller inquiry resulted in the president’s “complete and total exoneration.”

Slideshow ( 37 images )

“Did you actually totally exonerate the president?” Nadler asked Mueller during the first hearing.

“No,” Mueller replied.

Mueller testified that his inquiry was conducted in “a fair and independent manner” and that members of the special counsel’s team “were of the highest integrity.”

Trump, however, was unsparing in his criticism.

“I think Robert Mueller did a horrible job, both today and with respect to the investigation,” Trump said, adding that as special counsel, Mueller “ruined people’s lives” and was part of an attempted “illegal overthrow.”

Slideshow ( 37 images )

“There was no defense to this ridiculous hoax, this witch hunt that’s been going on for a long time,” Trump added.

Mueller testified that the investigation was neither a witch hunt nor a hoax.

MUELLER’S REVERSAL

Mueller caused confusion when he testified while being questioned by Democratic Representative Ted Lieu during the first hearing that he would have sought to indict Trump were it not for a Justice Department policy against bringing criminal charges against a sitting president. But hours later at the outset of the second hearing, Mueller corrected himself.

“As we say in the report and as I said at the opening, we did not reach a determination as to whether the president committed a crime,” Mueller said.

Mueller added that a president could be charged with a crime after leaving office.

Democrats entered the hearings hoping his testimony would rally public support behind their own investigations of the president and his administration. Democrats are deeply divided over whether to launch the impeachment process set out in the U.S. Constitution for removing a president from office for “high crimes and misdemeanors.”

Trump has accused Mueller of having conflicts of interest, including saying Mueller wanted the president to appoint him as FBI director after firing James Comey in May 2017. Mueller disputed Trump’s account, saying he had not sought the FBI job from Trump. The Justice Department named Mueller as special counsel later that month.

Questioned by Democrat Val Demings, Mueller said he “generally” agreed that Trump’s written answers to his investigators were not always truthful after the president refused to submit to a face-to-face interview. Mueller also said his team decided not to exercise its subpoena powers against Trump to force an interview last year because of “the necessity of expediting the end of the investigation.”

Asked about Trump’s past comments praising WikiLeaks - the website that published stolen Democratic emails the inquiry found were hacked by Russians to harm Trump’s election opponent, Hillary Clinton - Mueller said: “‘Problematic’ is an understatement.”

“Let me say one more thing,” Mueller said. “Over the course of my career, I have seen a number of challenges to our democracy. The Russian government’s effort to interfere with our election is among the most serious.”

Under questioning, Mueller said his report detailed “multiple acts by the president that were capable of exerting undue influence over law enforcement investigations, including the Russian interference and obstruction investigations.”

He added: “The finding indicates ... that the president was not exculpated for the acts that he allegedly committed.”

Mueller’s investigation led to criminal charges against 34 people and three Russian entities. People who were convicted at trial or pleaded guilty included Trump’s former campaign chairman, deputy chairman and other aides.