Senate Majority Leader Mitch McConnell on Tuesday ripped House Democrats' impeachment proceedings against President Donald Trump as the "most unfair" in U.S. history and rejected Democrats' call for new witnesses as part of the Senate trial.

In a forceful Senate floor speech, McConnell slammed Senate Minority Leader Chuck Schumer for requesting that the Senate, during its trial, call former national security adviser John Bolton and acting White House chief of staff Mick Mulvaney, as well as two others, to testify about Trump’s Ukraine dealings.

"It is not the Senate's job to leap into the breach and search desperately for ways to get to guilty," McConnell, R-Ky., said. "The fact that my colleague is already desperate to sign up the Senate for new fact-finding … which House Democrats themselves were too impatient to see through, well, that suggests something to me. It suggests that even Democrats who do not like this president are beginning to realize how dramatically insufficient the House's rushed process has been."

He also shredded the entire impeachment process by House Democrats as a “slapdash work product” that was “dumped on us in the Senate” and that “has failed to come anywhere near the bar for impeaching a duly elected president, let alone removing him for the first time in American history."

McConnell repeatedly called it “the most rushed," "most unfair," and "least thorough presidential impeachment in our nation's history.”

“By any ordinary legal standard, what House Democrats have assembled appears to be woefully inadequate to prove what they want to allege,” he added.

McConnell was responding to a proposal from Schumer, D-N.Y., Sunday night that called for Bolton and Mulvaney to be witnesses at an impeachment trial for Trump.

Schumer, in a letter to McConnell, proposed that the Senate subpoena four people who are close to the president or are expected to know about the delay of about $400 million in military aid to Ukraine: Mulvaney; Bolton; Robert Blair, senior adviser to Mulvaney; and Michael Duffey, associate director for national security at the Office of Management and Budget.

McConnell, on Tuesday, excoriated his colleague for his “11-paragraph letter” that was “delivered by way of the news media.”

The “preferable path,” McConnell said, “would have been an in-person conversation, which I nonetheless still hope to pursue.”

He said he would prefer to see an agreement about a Senate trial similar to one reached regarding the 1999 Senate impeachment trial of President Bill Clinton. Back then, there was an agreement to hear the prosecution and then the defense arguments, and then vote on whether to have witnesses or not.

"We certainly do not need jurors to start brainstorming witness lists for the prosecution and demanding to lock them in before we have even heard opening arguments," McConnell said.

Moments later, Schumer responded with his own floor speech, retorting that he “did not hear a single sentence, a single argument as to why the witnesses I suggested should not give testimony” in a Senate trial.

“Why is the leader, why is the president, so afraid of having these witnesses come testify?” Schumer said. He added that he wanted McConnell to provide “specific” reasons his requested witnesses shouldn’t testify.

“A trial without witnesses is not a trial,” Schumer added. “It’s a rush to judgment, it's a sham trial.”

Schumer, nevertheless, said that he still hoped he and McConnell “can sit down” to hash out the details for a Senate trial.