Opening with a bit of self-deprecating congressional humor, Schiff noted "how rare it is, how extraordinary it is" for House members to hold the undivided attention of senators "for hours or even for minutes".
It follows a day of presentations and argument in which Democratic impeachment managers implored skeptical Republicans to buck their party's leadership and vote to remove the president for abusing the power of his office and obstructing Congress.
At the start of President Donald Trump's impeachment trial on Wednesday, House impeachment manager Adam Schiff said Trump had pushed Ukrainian President Volodymyr Zelenskiy to investigate former Vice President Joe Biden and his son on unsubstantiated corruption charges a year ago.
Schiff, a Democrat who leads the House Intelligence Committee, was one of seven House managers serving as prosecutors who laid out the framework of the case against Trump during the initial eight-hour session.
Trump again ridiculed the Democrats' impeachment case, saying on Twitter, "The Democrat House would not give us lawyers, or not one witness, but now demand that the Republican Senate produce the witnesses that the House never sought, or even asked for?"
"I'd sort of love to sit in the front row and stare in their corrupt faces", Trump said, adding that his legal team "might have a problem" with it.
Trump has denied wrongdoing and called the impeachment an "attempted coup".
"His counsel might recommend against that", he said with a laugh. Across six networks, they watched. Trump has dismissed the trial as a "hoax" and maintained he did nothing wrong.
"To a lot of Americans, they are like yeah, I do that every day at work", the Fox News co-host said, adding "You can do your job". Such an announcement, House Democrats say, would politically benefit Trump's re-election prospects.
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Donald Trump could be the first president in history to be removed from office.
"Witness testimony, text messages, emails, and the call record itself confirm a corrupt quid pro quo for the White House meeting, an official act, available only to the president of the United States", Schiff told senators on Wednesday.
The White House has been stonewalling subpoenas after a call summary of a phone call between Mr Trump and the Ukrainian president galvanised the impeachment case.
The president's acquittal is all but certain.
Nearly two-thirds of Americans believe Trump has definitely or probably done things that are illegal, either while in office or when he was running for president, according to a Pew Research Center poll released Wednesday.
Bolton refused to cooperate with the House inquiry but made a surprise announcement on January 6 that he would be willing to testify in the Senate trial if subpoenaed to do so.
The trial began in earnest on Tuesday with a marathon session of debate that ultimately culminated in a partisan vote in favour of Senate Majority Leader Mitch McConnell's resolution outlining the rules for the impeachment trial, while 11 amendments proposed by Democrats were voted down. There are no indications right now that any GOP senators will break with their leadership.
Mr Trump's defence team is expected to begin their rebuttal on Saturday. It was indiscriminate and historically unprecedented.
Several prominent Republican senators-including Majority Leader Mitch McConnell and Senate Judiciary Committee Chair Lindsey Graham-have characterized the impeachment push as partisan electioneering, created to smear the president ahead of the November election.