It's the second day of Democrats laying out their case to remove President Donald Trump from office.
Here are three things to know:
Democrats use GOP words during Clinton against them
Trump's legal team won't be able to lay out their defense until House Democratic impeachment managers use up their allotted 24 hours.
But lawyer Alan Dershowitz seemed to tip his hand earlier this week when he said on ABC's "This Week" that "abuse of power" isn't an impeachable offense under the Constitution.
So perhaps it wasn't a coincidence that House Democratic impeachment manager Rep. Jerry Nadler used much of his time on Thursday to try to dismantle that argument.
In one remarkable moment, he played a video clip of Graham in 1999 making the case that a president can be removed from office for abuse of power, even without being convicted of a crime. Graham was not in his seat at the time the video clip played.
"You don't even have to be convicted of a crime to lose your job in this constitutional republic if this body determines that your conduct as a public official is clearly out of bounds in your role," Graham said at the time. "Impeachment is not about punishment. Impeachment is about cleansing the office. Impeachment is about restoring honor and integrity to the office."
In comments unearthed by CNN, Dershowitz said in 1998 that "it doesn't have to be a crime if you have somebody who completely corrupts the office of president and who abuses trust and who poses great danger to our liberty, you don't need a technical crime."
Democrats invoked history, from George Washington to Richard Nixon
Democrats repeatedly referred to historical figures to make their case.
Nadler insisted that "no president has abused his power in this way" since George Washington took office in 1789. He noted a letter from John Adams to Thomas Jefferson warning of foreign influence in U.S. elections. And he noted other framers who wrote of the need for impeachment to remove potentially corrupt presidents.
And Democrats again cited a quote from Alexander Hamilton warning of a man "unprincipled in private life, desperate in his fortune, bold in his temper, known to have scoffed in private at the principles of liberty" whose goal is to "throw things into confusion that he may ride the storm and direct the whirlwind."
Of Trump's actions, Nadler said at one point, "It puts even President Nixon to shame."
Trump allies protested with fidget spinners, books and sketches
Staying alert remained a bipartisan struggle on Thursday, as senators repeatedly rose from their seats and paced the back wall or wandered back to their cloakroom off the Senate floor.
And while some senators appeared to doze off at points -- including Democratic Sens. Elizabeth Warren and Bernie Sanders -- most senators appeared to pay attention, with more moderate and vulnerable Republicans, such as Sens. Susan Collins and Mitt Romney – perhaps mindful of the optics – appearing eager to listen.
Still, several Trump allies on Thursday seemed to go out of their way make their point that the trial was frivolous. At a lunch of GOP senators, Republican Sen. Richard Burr of North Carolina handed out stress balls and fidget spinners -- more common in elementary schools than the Senate chamber. Burr could be seen playing with his spinner, while Republican Sens. Pat Toomey of Pennsylvania and Tom Cotton of Arkansas had spinners sitting on their desks.
Before launching into a third day of arguments, Schiff said it was "extraordinary" to have such a captive audience of senators.
"Of course, it doesn't hurt that the morning starts out every day with a Sergeant-at-Arms warning you that if you don't, you will be imprisoned," he said, a reference to 18th century language still used by the Senate during impeachments.
ABC News' Devin Dwyer, Trish Turner, Beatrice Peterson, Ben Gittleson, Allison Pecorin, Katherine Faulders, Mariam Khan, Sarah Kolinovsky and John Parkinson contributed to this report.