(CNN) -- It's day two for House Democrats to convince senators that President Donald Trump should be removed from office — and a test for senators who seem to be growing more restless by the hour as the impeachment trial drags on.
Democrats will focus Thursday's presentation on the constitutional case for removing Trump for his abuse of power, one of two articles of impeachment passed by the House last month. They plan to lean into evidence they gathered in their investigation to argue the President used his office to try and extract investigations into his political rivals while withholding US security aid and a valued White House meeting.
"We will go through the law, the Constitution, and the facts as they apply to Article I," House Intelligence Chairman Adam Schiff, a California Democrat and lead impeachment manager, said Wednesday evening previewing the House's presentation for the following day. "We've introduced the case. We've gone through the chronology. And (Thursday) we will apply the facts to the law as it pertains to the President's abuse of power."
But the challenge for presenters is growing more arduous as senators struggle to stay engaged in a narrative many feel they've heard before.
"Certainly senators are struggling to try to see why we have to sit there, sit hearing the same arguments over and over and over and over again," said Sen. John Cornyn, a top Republican from Texas.
Still, Democrats are looking to use their 24 hours for opening arguments, which is spread across three days, to drop new information that takes senators — and the press by surprise. In fact, part of their argument is that they need additional witnesses and documents to obtain new information that would supplement what they describe as overwhelming evidence of the President's guilt.
But Democrats' focus is on building a complete case — one that's targeted at a small group of Senate moderates they hope they can convince to cross the aisle and vote with them on key witnesses like the President's former national security adviser John Bolton and acting White House chief of staff Mick Mulvaney. While a group of three Republicans have hinted they could be open to — Sens. Susan Collins of Maine, Lisa Murkowski of Alaska and Mitt Romney of Utah — Democrats would need to convince four in order to have the votes they would need to issue subpoenas for documents and witnesses.
"The same Republicans saying they heard nothing new just voted nine times on Tuesday to hear nothing new. If they want new stuff, there's plenty of it," said Senate Minority Leader Chuck Schumer, a reference to votes on amendments to the trial rules to obtain new witness testimony and evidence. "As the managers made clear, a lot of the documents are sitting there, all compiled, all ready to go, with simply a vote of four republicans to subpoena them."
On Wednesday, the seven House managers, led by Schiff, moved meticulously through the timeline of their case against the President, describing a months-long effort that began with the ouster of the US ambassador to Ukraine that led to the hold-up of US aid to Ukraine and the pressure campaign for Kiev to announce an investigation against the President's political rivals.
At the same time, the President's allies are also working behind the scenes to lobby wavering GOP senators to oppose any witnesses, a source familiar with the process told CNN. The effort includes calls not only from members of the President's team and allies on Capitol Hill, but also identifying people that the senators trust and respect from a wide variety of places, including back home, and getting them to call.
That vote on whether to have witnesses and obtain additional documents would likely happen next week after opening arguments from both sides and 16 hours of time for senators to ask questions concludes.
On the Senate floor, the long hours where senators are required to stay but not speak is taking its toll on a body where the average age is about 63 years old.
While Senate rules encourage members to be seated in their desks during the remainder of the trial, long days and sometimes longer nights have worn members down. While breaks in decorum that the first day of arguments didn't surface until the late hours of the night, on Wednesday they were happening earlier and earlier inside the chamber.
Senators have taken to pacing around the chamber and standing behind their desks to keep from falling asleep at their desks. Many senators are writing during the trial, both to take notes but also to keep engaged.
Wednesday evening, Sen. Rand Paul, a Republican from Kentucky was spotted with a crossword puzzle. Sen. Bernie Sanders, a 2020 presidential hopeful from Vermont, was seen whispering to his fellow Presidential contender Amy Klobuchar of Minnesota during the trial, and GOP Sen. Tom Cotton of Arkansas enjoyed glasses of milk, one of two accepted beverages for the floor. Democratic Sen. Dianne Feinstein of California was nowhere to be seen in the final hour of Wednesday's session.