President Donald Trump claimed Sunday that his lawyers "absolutely shredded" Democrats' case that he should be convicted of impeachment charges and removed from office.
A day after Trump's lawyers began their defense of him at his Senate trial, he said on Twitter, "The Impeachment Hoax is a massive election interference the likes of which has never been seen before.
He attacked the Democrats' lead prosecutor in the case, Congressman Adam Schiff, as "a CORRUPT POLITICIAN, and probably a very sick man. He has not paid the price, yet, for what he has done to our Country!"
Trump's trial resumes Monday before the 100 U.S. senators deciding his fate, with his lawyers laying out their argument that he did nothing wrong in asking Ukraine last July to launch an investigation of one of his chief 2020 Democratic rivals, former Vice President Joe Biden.
White House counsel Pat Cipollone began his defense Saturday during two hours of arguments on the two impeachment charges Trump is facing -- that Trump abused his presidency and obstructed congressional efforts to investigate his Ukraine-related actions.
Cipollone said Trump's legal team does not believe that Democrats from the House of Representatives prosecuting the case came "anywhere close to meeting their burden" that Trump committed "high crimes and misdemeanors" -- the U.S. Constitution's standard for impeachment and removal from office.
WATCH: Trump Impeachment Defense Closes First Week of Trial
Now, Cipollone and other Trump defense attorneys have said they will expand on their defense, in part focusing on why they believe there was nothing wrong with Trump's request last July to Ukrainian President Volodymyr Zelenskiy to investigate Biden, his son Hunter Biden's work for a Ukrainian natural gas company and a debunked theory that Ukraine meddled in the 2016 U.S. election to undermine Trump's campaign. No evidence has ever surfaced against the Bidens.
Over three days last week, seven House Democrats laid out their case that Trump endangered U.S. national security to benefit himself politically by asking for the Biden investigations by Ukraine at the same time he was withholding $391 million in military aid that Kyiv wanted to help fight Russian-backed separatists in eastern Ukraine.
"The evidence against the president is overwhelming," Congresswoman Val Demings, one of the House impeachment managers, told ABC News' "This Week" show on Sunday.
WATCH: Democrats Make Case Trump Abused Power of Presidency
Criminal defense attorney Alan Dershowitz, part of Trump's legal team, told "Fox News Sunday" that he will argue that there is not a "legally constitutional" argument that Trump can be impeached. He claimed that the offenses he is accused of have "to be a crime," a contention disputed by scholars supporting Trump's impeachment in the House and conviction in the Senate.
Trump released the defense aid to Ukraine in September after a 55-day delay, even though Zelenskiy had not opened the Biden investigations. Republicans say that is proof that Trump had not engaged in a reciprocal deal with Kyiv -- the military aid in exchange for the politically tinged investigations Trump wanted. Democrats say he did so only after the alleged scheme was exposed.
Trump's impeachment trial is only the third such event in U.S. history. After Trump's lawyers finish their defense of the country's 45th president, possibly by Monday evening, 16 hours have been set aside for the senators to ask questions of the House managers and the Trump lawyers.
With the completion of the question-and-answer session, Democrats then are expected to resume their efforts to try to get the Senate to vote to subpoena key witnesses familiar with Trump's actions, specifically former national security advisor John Bolton and acting White House chief of staff Mick Mulvaney and others in Trump's orbit, as well as Ukraine-related documents from the White House, State Department and Defense Department.
WATCH: Vote Expected This Week on Allowing Witnesses
But Republicans, led by Senate Majority Leader Mitch McConnell, are opposed to calling witnesses and subpoenaing documents and instead are hoping to acquit Trump by week's end, just days ahead of his annual State of the Union address to Congress on Feb. 4.
With Republicans holding a 53-47 majority in the Senate, Democrats will need the votes of four Republicans to secure a majority calling for witnesses and more documents, but so far do not have assurances of four Republican votes.
If Democrats are successful in winning the votes to have Bolton and Mulvaney testify, Trump has said Republicans should call the Bidens to testify, along with the still-unidentified government intelligence whistleblower who first disclosed Trump's request that Ukraine investigate the Bidens.
House impeachment manager Schiff said that "the president has a right to call relevant witnesses, not irrelevant witnesses." Schiff said the president should not be allowed to use his impeachment trial "to smear his opponent. Hunter Biden cannot tell us anything about military aid to Ukraine" or Trump's thinking about whether to schedule the White House meeting that Zelenskiy wanted.
The two leaders eventually met on the sidelines of United Nations meetings but not at the White House.
If the Democrats' subpoena efforts fall short, McConnell could move quickly to vote on the two articles of impeachment, which Trump is all but assured of winning since a two-thirds vote is needed for Trump's removal from office. No Republican has called for Trump's ouster.
On Saturday, Cipollone reiterated the oft-repeated criticism of the Democratic-led impeachment proceedings that they are trying to nullify Trump’s 2016 election win and keep him off the November 2020 ballot when he is seeking a second term in the White House.
"They’re here to perpetrate the most massive interference in an election in American history and we cannot allow that to happen,” Cipollone said. “It would violate our Constitution. It would violate our history. It would violate our obligations to the future. And, most importantly, it would violate the sacred trust that the American people have placed in you.”
In a two-hour session, White House deputy counsel Michael Purpura played a video clip of lead House manager Adam Schiff embellishing the conversation Trump had with Zelenskiy during a July 25 phone call that is central to the impeachment probe.
"That’s fake. That’s not the real call, that’s not the evidence,” Purpura said in an attempt to discredit Schiff and other Democrats.
Schiff said after the hearing that his recounting of the Trump-Zelenskiy call during the House impeachment investigation was “in character with what the president was trying to communicate.”
During the July call, Zelenskiy told Trump that Ukraine sought more U.S. military assistance. Trump responded, “I would like you to do us a favor, though,” and then asked Zelenskiy to investigate the Bidens. Trump's lawyers contend that the "us" refers to the United States, not Trump personally.
Even though the aid embargo was lifted in September, Congressman Jason Crow said during the House impeachment managers' closing arguments Friday, "It was only lifted because President Trump had gotten caught.” Shortly before the release of the aid, a still-unidentified government intelligence official filed a complaint against Trump for soliciting a foreign government's help in investigating a political rival.
But Purpura said Saturday that Ukraine did not become aware of Trump’s hold on the military aid until the latter part of August, well after the fateful July 25 call.
"There can’t be a threat without a person knowing he’s being threatened,” Purpura said. “There can’t be quid pro quo without the quo.” Democrats contend that Ukraine was already asking about the delay in the aid around the time of the Trump-Zelenskiy conversation.
Trump is only the third U.S. president to be impeached and tried before the Senate. Andrew Johnson was impeached in 1868 because of a post-Civil War dispute over states that seceded from the union. Bill Clinton was impeached in 1998 for lying to a grand jury over a sex scandal. Both Johnson and Clinton were acquitted and remained in office until the end of their terms.