Prosecutors in the trial of Roger Stone told jurors Wednesday that the longtime Donald Trump confidant repeatedly lied to Congress "because the truth looked bad" for the president.

The opening arguments in the case against Stone, a longtime Republican operative and provocateur, made clear that the president will be a central figure in the trial, even though the charges aren't directly related to his interactions with Trump. Stone is accused of lying to Congress, tampering with a witness and obstructing the House investigation into whether the Trump campaign coordinated with Russia to tip the 2016 election.

Stone was indicted in January as part of special counsel Robert Mueller's investigation into Russian electoral tampering. Mueller found that Russia tried to help Trump's candidacy, but there wasn't enough evidence to support criminal charges that the Trump campaign conspired with Russia.

"The evidence in this case will show that Roger Stone lied to the House Intelligence Committee because the truth looked bad for the Trump campaign and the truth looked bad for Donald Trump," Assistant U.S. Attorney Aaron Zelinsky told jurors in a Washington courtroom.

The Trump connection was also highlighted by the first prosecution witness, Michelle Taylor, a former FBI agent who had served on Mueller's team. She listed a flurry of phone calls between Stone and then-candidate Trump — including three calls on July 14, 2016 — the day that a massive hack of the Democratic National Committee's servers was reported. But Taylor said she did not know what was discussed on those calls.

Zelinsky, also a veteran of Mueller's team, cast the case against Stone in stark, simple terms. Stone, he said, categorically denied any written communication with anyone regarding Julian Assange, the founder of the anti-secrecy site WikiLeaks, which published the stolen emails. Then Zelinsky showed half a dozen emails and text messages with Stone discussing Assange with different people. One email, asking an associate to try to contact Assange, came an hour after Stone and then-candidate Trump spoke on the phone.

Government lawyers later showed several interviews in which Stone claimed that he had "back-channel communication" with Assange and that they had "communicated through a trusted mutual friend."

Defense attorney Bruce Rogow didn't deny that Stone had said things that were untrue before the House committee. Rogow described his client as a natural braggart whose claims of insider information didn't match reality.

"He did brag about his ability to try to find out what was going on," Rogow said. "There was no intermediary between Mr. Stone and Julian Assange. It's made-up stuff."

Rogow repeatedly focused on Stone's "state of mind" and intentions heading into the hearing. He said his client offered to testify willingly and contended that lawmakers misled Stone into thinking the hearing would focus solely on Russian interference, then ambushed him with questions about WikiLeaks.

"We think the evidence will show that there was no corrupt intent in whatever was said or done by Mr. Stone," Rogow said. "He went without a subpoena. That's not the usual way that people go about things if they're intending to lie."

Zelinsky said jurors would hear testimony from Steve Bannon, the former White House chief strategist, and from Rick Gates, the associate of Trump's former campaign chairman Paul Manafort who pleaded guilty to charges in Mueller's investigation and has agreed to cooperate with prosecutors.

The trial is expected to last two to three weeks.