WASHINGTON – Jon Tester wrote about the need to call witnesses “NOW.” Tina Smith scribbled “protecting the election” – and underlined it. With a blue pen, Tim Scott declared “What a hot mess!”

For 13 days, 100 senators absorbed the arguments during the impeachment trial – and ultimate acquittal – of President Donald Trump. They weren't allowed to speak but they had a lot to say.

Prohibited from using phones or computers, members could only record their thoughts on one of the most consequential votes of their careers using the same technology they used in grade school: pen and paper.

And by doing so, senators instantly created historical artifacts.

USA TODAY reached out to dozens of senators and asked for a few pages of their notes during the trial. Seven of them – three Republicans and four Democrats – shared part of what they wrote. What they provided offers a glimpse of what senators, who acted as jurors in the historic proceedings, thought was important to record at the time – in their own words and in their own handwriting.

Some filled multiple notebooks, legal pads or small, bound journals at their mahogany desks as they sipped from glasses of milk or water. Others jotted just a few thoughts while others copied verbatim arguments from House impeachment managers and members of Trump's defense team. In black and blue ink, they underlined, starred, circled and bullet-ed what stood out to them.

Here’s what they shared:

Sen. Jon Tester, D-Mont., writes through witness debate

The first day of the trial on Jan. 21 turned into a marathon session that ended early the next morning. And Tester was taking notes.

He penned a quote from lead House impeachment manager Adam Schiff, D-Calif. on the need for more information, including from top Trump aides: “Senate needs to subpoena evidence and witnesses NOW to further get info on the president’s actions further explaining the president’s actions, including Mulvaney, Duffy, Blair, Pompeo, Perry, Bolton.”

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“President claims no testimony because it violates National Security – the very National Security that Trump violated," he added.

Later, Tester captured points Trump’s lawyers were making: “Impeachment is an abuse of power."

Then he noted the lawyers’ criticism that the House refused to send over the charges to the Senate for weeks while they tried to negotiate for witnesses: “Held onto impeachment articles 33 days.”

Sen. Tim Scott, R-S.C.: 'What a hot mess!'

At times, emotion bled onto the page.

As Schiff outlined Democrats' case in his opening remarks over the first few days of the proceedings, Scott picked up his blue pen and took down some of the impeachment managers' argument that Trump’s conduct was a “consistent thread throughout the presidency.”

“Impeachment is a weapon of last resort,” Scott wrote.

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He also put down three Fs: fairness, fiction and fabrication: For fairness, he asserted that the trial had a "fundamental lack" of it; for fiction, he noted the proceeding “hangs on Schiff’s acting skills, not the facts;" and for fabrications, he wrote the proceedings equaled “100% deception.”

At the end of the page, a final thought was underlined, “What a hot mess!”

Notes from Sen. Tim Scott, R-S.C., during the impeachment trial of President Donald Trump. Photo provided by the office of Sen. Tim Scott

Sen. Bob Menendez, D-N.J., focuses on opening prayer

Menendez filled 240 pages of notes during the trial, always using a blue pen, and shared two with USA TODAY.

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On Jan. 22, as both sides offered their opening arguments, he remarked on the invocation from U.S. Senate Chaplain Barry Black, who asked God to help senators “remember that patriots reside on both sides of the aisle, that words have consequences, and that how something is said can be as important as what is said.”

“Chaplain Black gives a very interesting prayer about patriots on both sides, and civility in words,” Menendez wrote.

Sen. Tina Smith, D-Minn., on 'protecting' elections

On Jan. 29 as senators, one-by-one, stood up and submitted questions to House managers prosecuting the case and the president’s defense team, Smith took her blue, felt-tipped pen and composed some notes in the pages of her bound, red notebook.

She recorded some of Schiff’s response to an allegation House managers were trying to overturn an election.

“Not voiding the election, protecting the election,” she put, underlining the word protecting.

She then raised the question at the heart of the impeachment case: ““The question is did President commit high crime[s] & misdemeanors?”

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Notes used by Sen. Tina Smith (D-MN) during the impeachment trial of US President Donald J. Trump. Photo provided by the office of Sen. Tina Smith

Sen. Lisa Murkowski, R-Alaska, noted the Ukraine aid dates

Murkowski’s thoughts on the proceedings were pivotal. A key swing vote, both sides sought to persuade her on the question that lingered over the trial, whether additional witnesses should be called.

Two days before she would ultimately vote against the idea on Jan. 31 — Murkowski penned questions she and fellow senators asked.

More: Murkowski says she’s a ‘no’ vote on calling witnesses, virtually assuring Bolton, Mulvaney won't appear at Trump trial

She scribbled in black ink a question from Sen. Dick Durbin, D-Ill., about executive privilege, noting in brackets the response from the managers was a “non answer.”

Under that, she wrote in cursive a question from fellow Republican Sen. Mitt Romney of Utah, who asked what date the president ordered the hold on military aid to Ukraine. She took down and crossed out dates that the president’s attorney listed.

At the bottom of the page was a question she asked. Instead of listing her name, she scrawled her initials “LAM” and crafted down her query about why the House did not reissue rejected subpoenas before it voted to authorize its impeachment inquiry.

In the small notebook, she meticulously detailed several of the key explanations, including that it was a “red herring” and that the House has the authority “to set their rules.”

Notes used by Sen. Lisa Murkowski (R-AK) during the impeachment trial of US President Donald J. Trump. Photo provided by the office of Sen. Lisa Murkowski

Menendez pens argument about foreign interference

Menendez's pen started moving again during the question-and-answer round of the trial.

When Schiff answered a question from several Democratic senators about foreign interference in elections, he noted "One of the highest priorities to prevent things like what Russia did in 2016. It’s not OK to criminally conspire to collude with another country to get info, use it,” Menendez wrote.

He added: “You can’t solicit foreign interference, and a failed attempt to do so doesn’t exonerate you.”

Sen. Richard Blumenthal, D-Conn., scribbles on closing statements

During Schiff’s closing arguments Monday, Blumenthal scribbled parts of the California Democrat's speech in blue ink across two pages.

He put “truth matters” and that allowing Trump’s conduct would make the “election open [to the] highest bidder." Schiff also urged senators to act because it was “midnight in Washington," a phrase that appeared in Blumenthal's notes.

He added, “Single man of courage is a majority," a line he circled.

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Sen. Bill Cassidy, R-La., summarized the arguments

In black ink, Cassidy wrote"Impeachment Thoughts" at the top of his yellow legal pad, one of several he filled throughout the trial. Over the next three pages, he summarized some of the major arguments.

Under “goal of proceedings," he made bullet points, including that senators were tasked with determining whether “DT” – initials for Donald Trump – committed an offense and, “if so, is the offense impeachable.”

He mused about preserving the political process: “Don’t cheat America of ability to choose Pres[ident]." Appearing in his notebook were the words “reasonable people can disagree” about why the president withheld $400 million in military aid for Ukraine, an allegation at the heart of the Democrats' impeachment push.

He added the “pres[ident] not charged w/ qpq” (or quid-pro-quo) and “he was not charged w/ bribery.”

Over the days, Cassidy did more research, particularly on all the mentions of the Founding Fathers. He printed out a copy of "The Federalist" by Alexander Hamilton, underlining and circling passages about the role of the Senate in impeachment and Hamilton’s thoughts on the merits of removal.

Take a peek at the notes senators took during the impeachment trial During the hours of arguments in the Senate impeachment trial, Senators took notes of the proceedings. Now you can see what they were wrote. USA TODAY

Contributing: Deborah Berry, Maureen Groppe and Nicholas Wu