WASHINGTON (NewsNation Now) — House Democrats Wednesday formally began making their case that former President Donald Trump should be convicted for inciting insurrection in last month’s violence at the U.S. Capitol that interrupted the presidential electoral count and left several people dead.

The trial proceeded Wednesday, NewsNation will live stream the impeachment proceedings here. House Democrats prosecuting the case and the former president’s attorneys laid out their opposing arguments before the senators, who are serving as jurors.

Prosecutors in Trump’s impeachment trial said they would prove that Trump was no “innocent bystander” but the “inciter in chief” of the deadly attack at the Capitol aimed at overturning his election loss to Joe Biden.

Opening the first full day of arguments, the House Democrats methodically presented evidence from the former president himself — hundreds of Trump tweets and comments that culminated in his Jan. 6 rally cry to go the Capitol and “fight like hell” to overturn his defeat.

“To us it might’ve felt like chaos and madness, but there was method to the madness that day,” U.S. Representative Jamie Raskin said in opening remarks, arguing President Trump’s complicity in the riot.

Raskin said House Managers will show never-before-seen footage of the Capitol insurrection as evidence. He warned parents and teachers to shield children who might be watching, saying the videos would show scenes of “shocking violence and bloodshed” against police officers.

Rep. Joe Neguse said the managers would lay out “months-long effort” from Trump to incite and enrage his supporters.

In hundreds of tweets, remarks and interviews as far back as spring and summer, managers said Trump was spreading unfounded claims about the election and refusing to commit to the peaceful transfer of power once it was over.

“Trump realized last spring that he could lose the November election and began planting seeds of anger among his supporters by saying he could lose only if it was stolen,” said Neguse. “If we are to protect our republic and prevent something like this from ever happening again, he must be convicted.”

Neguse argued that Trump knew what would happen when he took to the microphone at the outdoor White House rally on Jan. 6, almost to the hour that Congress gaveled in to certify Biden’s win.

“This was not just a speech,” he said. Trump’s supporters were prepped and armed, ready to descend on the Capitol, Neguse said. “When they heard his speech, they understood his words.”

The mob “didn’t come out of thin air,” echoed Rep . Joaquin Castro, D-Texas.

The start of trial arguments comes after a divided Senate decided that his impeachment trial could proceed even though Trump has already left office.

Senators on Tuesday voted 56-44 that it is constitutional to try a former president on impeachment charges. Republican Sen. Bill Cassidy of Louisiana joined Sens. Pat Toomey of Pennsylvania, Ben Sasse of Nebraska, Mitt Romney of Utah, Susan Collins of Main, and Lisa Murkowski of Alaska, in breaking party ranks and voting yes.

The day before, House prosecutors had senators relive the violent attack on Congress by playing a graphic video of what unfolded on Jan. 6. The video showed parts of the president’s rally speech to his supporters before they stormed the Capitol, as well as rioters ransacking the building and police trying to quell the mob. It also showed lawmakers trapped in the building as Trump’s supporters tried to stop the certification of Democrat Biden’s victory.

The Democrats accused Trump of committing an unforgivable offense by encouraging his backers to block the peaceful transfer of power, a hallmark of American democracy.

“If that’s not an impeachable offense, then there’s no such thing,” said Raskin, who delivered an emotional speech recounting how he became separated from his daughter and son-in-law during the violence.

Afterward, Trump’s lawyers argued that the former president’s rhetoric, including repeated claims without evidence that the election was stolen, is protected by the First Amendment’s guarantee of free speech and that the individuals who breached the Capitol were responsible for their own criminal behavior.

The lawyers sought to portray the trial as a sham, asserting that Democrats had weaponized impeachment to end Trump’s political career while ignoring basic principles of fairness and due process.

“We are really here because the majority in the House of Representatives does not want to face Donald Trump as a political rival in the future,” Bruce Castor, one of Trump’s lawyers, told senators.

The Democratic-led House impeached Trump one week after the riot, making him only the third U.S. president to be impeached and the first to be impeached twice.

Trump’s first impeachment trial, which stemmed from his efforts to pressure Ukraine to investigate Biden during the presidential campaign, ended in an acquittal a year ago in what was then a Republican-controlled Senate.

Party leaders have agreed on a fast-moving schedule that could lead to a vote on conviction or acquittal by early next week. Some Democrats had expressed concern that a prolonged trial could delay progress on Biden’s agenda, including a proposed $1.9 trillion coronavirus relief package.

Biden will not watch much of the trial, White House Press Secretary Jen Psaki said this week, adding he is focused on the pandemic rather than his predecessor’s fate.

“Joe Biden is the president, he’s not a pundit, he’s not going to opine on back and forth arguments,” she said.

When asked by reporters on Monday, the president declined to say whether he believed Trump should be convicted.

The Associated Press and Reuters contributed to this report. Reporting by AP’s Lisa Mascaro, Eric Tucker, Mary Clare Jalonick and Jill Covin; as well as Reuters’ David Morgan and Susan Cornwell.