WASHINGTON -- House prosecutors faced fidgeting senators as they rolled out their case against U.S. President Donald Trump on Wednesday, the trial's previous session having lasted a fatigue-inducing 13 hours. Trump was busy himself, returning from an international business conference but finding time to send 120-plus tweets that included trial commentary and criticism.

Highlights of Wednesday's session and what's ahead as senators conduct just the third impeachment trial of a president:

'CORRUPT SCHEME'

Rep. Adam Schiff, D-Calif., the lead prosecutor, spoke for more than two hours, laying out the case House Democrats made in weeks of hearings last year. Schiff, chairman of the House Intelligence Committee, said Trump had pursued a "corrupt scheme" to abuse his presidential power and then obstruct Congress' investigation.

He appealed to senators not to be "cynical" about the politics of impeachment, asking them to draw on the intent of the nation's Founding Fathers.

The founders "feared that a president could subvert our democracy by abusing the awesome power of his office for his own personal or political gain," Schiff said. "And so they devised a remedy as powerful as the evil it was meant to combat: Impeachment."

FIDGETY SENATORS

The challenge before Schiff and other House managers was clear, as they tried to win over not just fidgety senators sitting silently in the chamber but a divided American public. Senators were especially restless Wednesday, as lawmakers convened less than 12 hours after the marathon session that stretched to nearly 2 a.m.

Freshman Rep. Jason Crow, D-Colo., a House impeachment manager, had trouble holding the attention of senators, who by Senate rules were sitting in silence without access to phones or other electronics. Many senators left their seats and headed to nearby cloak rooms, or stood in the back or openly yawned as Crow talked about Trump's hold on military aid to Ukraine. At one point, more than 10 senators' seats were empty.

Crow, a military veteran who tried to emphasize the importance of the delayed aid to Ukraine, noticed the unusual level of activity, telling Chief Justice John Roberts at about 5 p.m. that he saw a lot of senators moving about. He wondered aloud if the Senate wanted to take a recess. No such luck. Roberts urged him to continue, and McConnell announced the Senate would not break until 6:30 p.m. for dinner.

A TRUMP TWEETSTORM

As Democrats presented their case, Trump blasted the proceedings from afar, joking that he would face off with Democrats by coming to "sit right in the front row and stare at their corrupt faces." Trump, who returned Wednesday from a global leaders conference in Davos, Switzerland, set a presidential record for activity on his favourite social media platform, sending at least 124 tweets in a single day, according to Factbase, a service that compiles and analyzes data on Trump's presidency.

The previous record for tweets was set on the day last month that the House Judiciary Committee opened its marathon session to approve two articles of impeachment against the president.

DEMONSTRATOR REMOVED

Just before dinner, Capitol police swiftly grabbed and dragged out of the chamber a man in the visitors' gallery who was yelling. As he was being held in a hallway outside the chamber, the gray-haired man could be heard shouting, "Dismiss the charges!" He also yelled "you're hurting me!" as police subdued him.

WHAT'S AHEAD

Democrats will continue arguments through Friday under rules approved by the Senate. Trump's lawyers will then have up to three days to rebut the Democrats' case. Trump's legal team passed on an opportunity Wednesday to file a motion to dismiss the case, an acknowledgement that there were not enough Republican votes to support it.

While polling suggests widespread agreement that Trump should allow top aides and former aides to appear as witnesses at the trial, that possibility seems remote.

In wrangling over rules for the trial that stretched into the early morning hours, Republicans shot down, one by one, Democratic efforts to get Trump aides to testify, including former national security adviser John Bolton, Secretary of State Mike Pompeo, and acting chief of staff Mick Mulvaney.

While some Republicans have expressed openness to new witnesses, it is unclear if four GOP senators will join Democrats to allow new testimony.

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Associated Press writers Lisa Mascaro, Aamer Madhani and Alan Fram contributed to this report.