Rep. Jamie Raskin, D-Md., argued for the historical precedent of impeachment, arguing that the Framers had impeachment of a person no longer in office in mind when drafting the Constitution.

"President Trump may not know a lot about the Framers, but they certainly knew a lot about him," Raskin said. "Given the Framers' intense focus on danger to elections and the peaceful transfer of power, it is inconceivable that they designed impeachment to be a dead letter in the president's final days in office when opportunities to interfere with the peaceful transfer of power would be most tempting and most dangerous, as we just saw."

Senators gathered on Tuesday for the historic second impeachment of Trump, the first trial of a former a president and one in which the lawmakers are themselves witnesses to the insurrection at the Capitol.

Here are photos of the Jan. 6 attack on the Capitol.

Rep. Jamie Raskin, D-Md., tapped by House Speaker Nancy Pelosi to serve as the lead House impeachment manager, opened arguments at Tuesday's trial, laying out the constitutionality of the Senate trial.

"You will not hear a lecture here because our case is based on cold, hard facts. It's all about the facts," Raskin said, before warning of the "dangerous" precedent it would set, if the Senate allowed a president to "get away with" committing an impeachable offense in the last few weeks of office, as he argues Trump did.

"This would create a brand new January exception to the Constitution of the United States of America. A January exception. And everyone can see immediately why this is so dangerous. It's an invitation to the president to take his best shot at anything he may want to do on his way out the door, including using violent means to lock that door, to hang onto the Oval Office at all costs, and to block the peaceful transfer of power," Raskin said.

"In other words, the January exception is an invitation to our Founders' worst nightmare. And if we buy this radical argument that President Trump's lawyers advance, we risk having Jan. 6 become our future. What will that mean for America? Think about it. What will the January exception mean to future generations if you grant it?" Raskin asked.

"I'll show you," he said, before playing a roughly 10-minute long video of inter-spliced footage of the Capitol attack, Trump's speech leading up to it and aftermath.

Raskin, a Harvard-educated, former constitutional law professor serving in his third term in the House, was the lead author of the impeachment article and began writing it from inside the Capitol on Jan. 6.

Impeachment manager Rep. Jamie Raskin, D-Md., argued in his opening statement that this case is a matter of protecting the Constitution, by pursuing high crimes.

"President Trump has sent his lawyers here today to try to stop the Senate from hearing the facts of this case. They want to call the trial over before any evidence is even introduced," Raskin said. "Their argument is that if you commit an impeachable offense in your last few weeks in office, you do it with constitutional impunity. You get away with it."

Trump's legal team has argued the trial is unconstitutional because Trump is no longer in office. Trump's team is denying he violated the oath of office. Its brief argues that Trump's use of social media and comments made on Jan. 6 are protected by the First Amendment.