For the third time in U.S. history, the Senate is holding an impeachment trial.

It begins next week with opening statements, and democrats are still demanding new witnesses testify.

Chief Justice John Roberts has taken over as presiding officer and senators have been sworn-in as jurors.  

Thursday, a government watchdog agency issued a legal opinion stating that President Trump's Administration violated the law by withholding military assistance to Ukraine.

President Trump wants the Senate to acquit him quickly; meanwhile, democrats are pressuring republicans to allow new witnesses to testify.

Senators are expected to vote on the rules of the trial next week.

Oklahoma Senator Jim Inhofe missed the swearing-in on Thursday due to a family emergency.

He plans to return to Washington on Tuesday where he will be sworn-in with no delay to the impeachment process.