Trump impeachment trial live updates: Biden makes 1st comments on acquittal

A Trump adviser told ABC News' Chief Washington Correspondent Jonathan Karl there was "very clear, deliberative strategy" behind Castor's speech and that the intention was to lower the temperature from Democrats' emotional opening.

Wrapping up his 45 minutes of speaking time, Castor said the defense "changed" their presentation because the House case was so "well done" and vowed to answer the House arguments later.

"I'll be quite frank with you, we changed what we were going to do on a count that we thought that the House managers' presentation was well done, and I wanted you to know that we have responses to those things," he said. "We have counter arguments to everything that they raised and you will hear them later on in the case."

Bruce Castor opened arguments for the defense team in a wide-ranging speech in which he first praised the arguments of the House impeachment managers and then took issue with -- arguing the nation's Founders didn't intend for former officials to face trial and, citing the First Amendment, that Trump should not be held accountable for his political speech.

"That's what we broke away from Great Britain in order to do," Castor said. "To be able to say what we thought."

"This trial is about trading liberty for security from the mob? Honestly, no. It can't be. We can't be thinking about that," he continued. "We can't possibly be suggesting that we punish people for political speech in this country. And if people go and commit lawless acts as a result of their beliefs and they cross the line, they should be locked up."

Castor said that none of the rioters have been charged for conspiring with Trump and called Democrats' argument that Trump violated the 14th Amendment "absolutely ridiculous."

One overarching point of Castor's was an argument heard in Trump's first impeachment trial -- that the Senate must reject this impeachment to prevent future trials or else, "The pressure will be enormous to respond in kind."

"The political pendulum will shift one day," Castor continued. "And partisan impeachments will become commonplace."

He also took issue with the House passing a single article of impeachment, which he deemed casting too wide of a net, rather than breaking it into parts.

"The article of impeachment is indivisible and the reason why that's significant is you have to agree that every single aspect of the entire document warrants impeachment because it's an all-or-nothing document. You can't cut out parts that you agree with," Castor said.

"We are really here because the majority of the House of Representatives does not want to face Donald Trump as a political rival in the future," he added. "Nobody says it that plainly, but unfortunately I have a way of speaking that way."

Trump attorney Bruce Castor opened by praising the "outstanding presentation" from House impeachment managers, noting what Rep. Jamie Raskin, D-Md., and his family endured "during that terrible day."

"You will not hear any member of the team representing former President Trump say anything but in the strongest possible way denounce the violence of the rioters and those that breached the Capitol, the very citadel of our democracy, literally the symbol that flashes on television whenever you're trying to explain that we're talking about the United States, instant symbol," Castor said.

Notably, Castor referred to Trump as "the former president," a term the Trump team has avoided using in their press releases.

Castor, a former Montgomery County, Pennsylvania, district attorney faced criticism in that role for declining to prosecute Bill Cosby in 2005.

The Senate returned from a 10-minute break following the arguments from the House impeachment managers.

Trump's legal team has taken the floor with Bruce Castor opening with his argument that it's unconstitutional to put a former president on trial.