WASHINGTON (AP) — Robert Mueller, the taciturn lawman at the center of a polarizing American drama, bluntly dismissed President Donald Trump’s claims of “total exoneration” Wednesday in the federal probe of Russia’s 2016 election interference. In a long day of congressional testimony, Mueller warned that Moscow’s actions represented — and still represent — a great threat to American democracy.

Mueller’s back-to-back Capitol Hill appearances, his first since wrapping his two-year Russia probe, carried the prospect of a historic climax to a rare criminal investigation into a sitting American president. But his testimony was more likely to reinforce rather than reshape hardened public opinions on impeachment and the future of Trump’s presidency.

With his terse, one-word answers, and a sometimes stilted and halting manner, Mueller made clear his desire to avoid the partisan fray and the deep political divisions roiling Congress and the country.

He delivered neither crisp TV sound bites to fuel a Democratic impeachment push nor comfort to Republicans striving to undermine his investigation’s credibility. But his comments grew more animated by the afternoon, when he sounded the alarm on future Russian election interference. He said he feared a new normal of American campaigns accepting foreign help.

He condemned Trump’s praise of WikiLeaks, which released Democratic emails stolen by Russia. And he said of the interference by Russians and others: “They are doing it as we sit here. And they expect to do it during the next campaign.”

His report, he said, should live on after him and his team.

“We spent substantial time assuring the integrity of the report, understanding that it would be our living message to those who come after us,” Mueller said. “But it also is a signal, a flag to those of us who have some responsibility in this area to exercise those responsibilities swiftly and don’t let this problem continue to linger as it has over so many years.”

Trump, claiming vindication despite the renewal of serious allegations, focused on his own political fortunes rather than such broader issues.

“This was a devastating day for the Democrats,” he said. “The Democrats had nothing and now they have less than nothing.”

Mueller was reluctant to stray beyond his lengthy written report, but that didn’t stop Republicans and Democrats from laboring to extract new details.