"To ensure fairness and restore integrity to the ongoing impeachment process, I request an expanded panel and a balanced composition of academic witnesses to opine on the subject matter at issue during the hearing", Collins wrote in a letter to committee chairman Jerrold Nadler on Saturday.
House Judiciary Democrat Zoe Lofgren, interviewed on CNN's "State of the Union" program, urged Republicans and her fellow Democrats to keep an open mind as they weigh possible impeachment charges against Trump.
But Collins continued to defend Trump.
"I do not believe it, so I'm not going to answer a hypothetical which is created to simply say that the president did something improper", Collins remarked, adding that "he did nothing improper". "If he has done nothing wrong, we're certainly anxious to hear an explanation of that".
Still, Republican Rep. Tom McClintock of California, a Judiciary Committee member, said he believes Trump would benefit if he presents his own defense.
On Sunday, House Judiciary Committee ranking member Doug Collins (R-GA) vowed to make House Intelligence Committee Chair Adam Schiff (D-CA) testify in the Judiciary committee's impeachment hearings.
Watch above, via Fox News Sunday.
Democrats are entering the next phase of their inquiry after a series of government witnesses sat before the intelligence committee and outlined their concerns about preconditions on Ukrainian aid.
Their number-one witness? House Intelligence Committee Chairman Adam Schiff, who is drafting a report that will form the factual basis for the judiciary panel's look at whether Mr. Trump should be impeached on allegations he sought political favors from Ukraine as a precondition for military aid.
It also will allege "an unprecedented campaign of obstruction in an effort to prevent the committees from obtaining evidence and testimony", Nadler wrote.
The House Intelligence Committee is expected to allow lawmakers to review its impeachment report on Monday (local time) ahead of a schedule vote to approve it Tuesday. On Tuesday, the Committee will hold a business meeting, following our regularly scheduled briefing, at 6 pm to consider and adopt the report.
The impeachment question is centered on Trump's petition last summer that Ukraine President Volodymyr Zelenskiy launch investigations to debunked claims the state interfered from the 2016 USA election which former Vice President Joe Biden, a Trump political competition, closed down an investigation into a Ukrainian energy company in which his son worked.
The Judiciary panel will decide whether to send impeachment charges to the full House for a vote.
In a letter dated Friday, Nov. 29, Nadler said President Trump has until December 6 to make his decision on the proceedings. "We expect to discuss the constitutional framework through which the House may analyze the evidence gathered in the present inquiry".
Sen. Amy Klobuchar (D-Minn.), who is running for president, described the impeachment inquiry as a constitutional obligation and likened the president's actions to a "global Watergate". "There is plenty of misconduct in the history of the United States among presidents but it's not all impeachable".