Congressional leadership of both parties will be out in full force on this week's Sunday network talk shows as both the Senate and the White House prepare for the impeachment trial that begins Tuesday.

House Intelligence Committee Chairman Adam Schiff Adam Bennett SchiffTop Democrats call for DOJ watchdog to probe Barr over possible 2020 election influence Overnight Defense: Top admiral says 'no condition' where US should conduct nuclear test 'at this time' | Intelligence chief says Congress will get some in-person election security briefings Overnight Defense: House to vote on military justice bill spurred by Vanessa Guillén death | Biden courts veterans after Trump's military controversies MORE (D-Calif.) will appear on ABC's "This Week," while House Judiciary Committee Chairman Jerrold Nadler Jerrold (Jerry) Lewis NadlerTop Democrats call for DOJ watchdog to probe Barr over possible 2020 election influence House passes bill to protect pregnant workers House Democrats postpone vote on marijuana decriminalization bill MORE (D-N.Y.) will be on CBS's "Face the Nation." Both lawmakers are impeachment managers, though Schiff is the lead manager on the prosecutorial team.

Senate Appropriations Committee Chairman Richard Shelby Richard Craig ShelbySenate GOP eyes early exit Dems discussing government funding bill into February GOP short of votes on Trump's controversial Fed pick MORE (R-Ala.) will join Schiff on "This Week," and Senate Judiciary Committee Chairman Lindsey Graham Lindsey Olin GrahamSenate Republicans face tough decision on replacing Ginsburg Democratic senator calls for eliminating filibuster, expanding Supreme Court if GOP fills vacancy What Senate Republicans have said about election-year Supreme Court vacancies MORE (R-S.C.) will appear on "Fox News Sunday."

The biggest debate surrounding the Senate impeachment trial is whether more witnesses will be called for testimony.

Democrats have pushed for Lev Parnas, an associate of President Trump Donald John TrumpObama calls on Senate not to fill Ginsburg's vacancy until after election Planned Parenthood: 'The fate of our rights' depends on Ginsburg replacement Progressive group to spend M in ad campaign on Supreme Court vacancy MORE's personal lawyer Rudy Giuliani Rudy GiulianiGrand jury adds additional counts against Giuliani associates Lev Parnas and and Igor Fruman Juan Williams: Breaking down the debates Giuliani criticizes NYC leadership: 'They're killing this city' MORE, to testify after documents released by the House this week revealed further information about the White House's involvement with Ukraine.

Parnas, during an interview with MSNBC's Rachel Maddow Rachel Anne MaddowMichael Cohen: Trump hates Obama because he's everything he 'wants to be' The Hill's 12:30 Report - Presented by Facebook - Trump floats 0M+ in personal spending for reelection bid Feehery: Unconventionally debunking the latest political conventional wisdom MORE that aired earlier this week, also implicated several allies close to the president, including former Energy Secretary Rick Perry Rick PerryOVERNIGHT ENERGY: Democrats push resolution to battle climate change, sluggish economy and racial injustice | Senators reach compromise on greenhouse gas amendment stalling energy bill | Trump courts Florida voters with offshore drilling moratorium OVERNIGHT ENERGY: Trump signs major conservation bill into law | Senate votes to confirm Energy's No. 2 official | Trump Jr. expresses opposition to Pebble Mine project Senate votes to confirm Energy's No. 2 official MORE, in the alleged pressure campaign to get Ukrainian President Volodymyr Zelensky to announce investigations into Trump's political rivals.

He also said the president was fully aware of what he was doing in Ukraine and that Vice President Pence and Secretary of State Mike Pompeo Michael (Mike) Richard PompeoHouse panel halts contempt proceedings against Pompeo after documents turned over Outgoing ambassador to China slams Beijing over coronavirus: 'Could have been contained in Wuhan' Hillicon Valley: FBI chief says Russia is trying to interfere in election to undermine Biden | Treasury Dept. sanctions Iranian government-backed hackers MORE were in the loop as well.

Parnas said he was a direct component of Giuliani's "shadow diplomacy" in Ukraine, including the former New York City mayor's efforts to have Trump recall then-U.S. Ambassador to Ukraine Marie Yovanovitch Marie YovanovitchGrand jury adds additional counts against Giuliani associates Lev Parnas and and Igor Fruman Strzok: Trump behaving like an authoritarian Powell backs Biden at convention as Democrats rip Trump on security MORE from her post.

Late last year, Parnas and Igor Fruman, another Giuliani associate, were arrested on campaign finance charges.

Giuliani's former associate also said former national security adviser John Bolton John BoltonDiplomacy with China is good for America The Hill's Morning Report - Sponsored by The Air Line Pilots Association - Pence lauds Harris as 'experienced debater'; Trump, Biden diverge over debate prep DOJ launches probe into Bolton book for possible classified information disclosures MORE would be able to shed light on the allegations against Trump if he was allowed to testify.

GOP lawmakers argued that Parnas's evidence should have been transmitted to the House earlier, but Parnas has claimed that all of his relevant documents had been seized by the Justice Department and were only recently released back to him.

Sen. John Cornyn John CornynBipartisan praise pours in after Ginsburg's death Chamber of Commerce endorses McSally for reelection Airline job cuts loom in battleground states MORE (R-Texas) has condemned the Soviet-born businessman and told reporters that Parnas "looks kind of like a shady character."

Graham added, “I wouldn't trust [Parnas] as far as I can throw him.”

The White House has chosen its impeachment trial defense team, which includes high-profile lawyers such as Alan Dershowitz Alan Morton DershowitzDershowitz suing CNN for 0 million in defamation suit Bannon and Maxwell cases display DOJ press strategy chutzpah Ghislaine Maxwell attorneys ask for delay to unseal court documents due to 'critical new information' MORE and Ken Starr.

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The full lineup of the shows is below: