Senators Mike Lee (R-UT) and Ted Cruz (R-TX) arrive for the beginning of the impeachment trial of U.S. President Donald Trump on Capitol Hill in Washington, U.S., January 16, 2020.

House impeachment managers, including lead manager House Intelligence Committee Chairman Adam Schiff (D-CA); Judiciary Committee Chairman Jerrold Nadler (D-NY); House Democratic Caucus Chairman Hakeem Jeffries (D-NY) and Rep. Jason Crow (D-CO), walk through the Ohio Clock Corridor as they arrive for the procedural start of the Senate impeachment trial of U.S. President Donald Trump in the U.S. Capitol in Washington, U.S., January 16, 2020.

U.S. Senator Lindsey Graham (R-SC) talks on a mobile phone during a break in the procedural start of the Senate impeachment trial of U.S. President Donald Trump at the U.S. Capitol in Washington, U.S., January 16, 2020.

Senator Chuck Grassley (R-IA), the president pro tempore of the U.S. Senate, swears in U.S. Supreme Court Chief Justice John Roberts to preside over the Senate impeachment trial of U.S. President Donald Trump in this frame grab from video shot in the Senate Chamber at the U.S. Capitol in Washington, U.S., January 16, 2020.

Protestors lay a banner calling for the removal of President Donald Trump inside of the Russell Senate Office Building during a demonstration on Capitol Hill in Washington, U.S., January 16, 2020.

A demonstrator wearing a 'Sam 2020' jacket rallies outside of the office of Senator Mitchell McConnell calling on U.S. President Donald Trump inside of the Russell Senate Office Building during a demonstration on Capitol Hill in Washington, U.S., January 16, 2020.

Senate Minority Leader Chuck Schumer (D-NY) listens as Senator Richard Blumenthal (D-CT) speaks to journalists after the beginning of the impeachment trial of U.S. President Donald Trump on Capitol Hill in Washington, U.S., January 16, 2020.

Protesters lay a banner with the Article of Impeachment calling for the removal of President Donald Trump inside of the Hart Senate Office Building during a demonstration on Capitol Hill in Washington, U.S., January 16, 2020.

Democratic U.S. presidential candidate Senator Bernie Sanders (I-VT) talks to reporters during a break in the procedural start of the Senate impeachment trial of U.S. President Donald Trump at the U.S. Capitol in Washington, U.S., January 16, 2020.

U.S. House Speaker Nancy Pelosi (D-CA) signs the two articles of impeachment of U.S. President Donald Trump before sending them over to the U.S. Senate during an engrossment ceremony at the U.S. Capitol in Washington, U.S., January 15, 2020. Image for illustrative purposes.

U.S. Senate Majority Leader Mitch McConnell (R-KY) signs an oath book along with all other members of the Senate, swearing to provide ?impartial justice? during the Senate impeachment trial of U.S. President Donald Trump in this frame grab from video shot in the Senate Chamber at the U.S. Capitol in Washington, U.S., January 16, 2020.

U.S. Senator Rand Paul (R-KY) is pursued by reporters as he arrives for the procedural start of the Senate impeachment trial of U.S. President Donald Trump at the U.S. Capitol in Washington, U.S., January 16, 2020.

U.S. Supreme Court Chief Justice John Roberts presides over the first session of the U.S. Senate impeachment trial of U.S. President Donald Trump in this frame grab from video shot in the U.S. Senate Chamber at the U.S. Capitol in Washington, U.S., January 16, 2020.

Reporters wear special credentials in the Senate subway, as movements are restricted during the President Donald Trump impeachment trial at the U.S. Capitol in Washington, U.S. January 16, 2020.

Senator Susan Collins (R-ME) (2nd R) departs after the beginning of the impeachment trial of U.S. President Donald Trump on Capitol Hill in Washington, U.S., January 16, 2020.

House Sergeant at Arms Paul Irving and House Clerk Cheryl Johnson carry two articles of impeachment against U.S. President Donald Trump during a procession with the seven House impeachment managers through the Rotunda of the U.S. Capitol to the U.S. Senate in Washington, U.S., January 15, 2020.

Chief Justice of the United States John Roberts swears in senators during the procedural start of the Senate impeachment trial of U.S. President Donald Trump in this frame grab from video shot in the Senate Chamber at the U.S. Capitol in Washington, U.S., January 16, 2020.

Police detain a protester during a demonstration calling for the removal of U.S. President Donald Trump inside of the Hart Senate Office Building, on Capitol Hill in Washington, U.S., January 16, 2020.

The U.S. Senate Sergeant at Arms Michael Stenger introduces the U.S. House impeachment managers, including lead manager House Intelligence Committee Chairman Adam Schiff (D-CA); House Judiciary Committee Chairman Jerrold Nadler (D-NY); Rep. Zoe Lofgren (D-CA); House Democratic Caucus Chairman Hakeem Jeffries (D-NY); Rep. Val Demings (D-FL); Rep. Jason Crow (D-CO) and Rep. Sylvia Garcia (D-TX) on the floor of the Senate as they arrive for the procedural start of the Senate impeachment trial of U.S. President Donald Trump in this frame grab from video shot at the U.S. Capitol in Washington, U.S., January 16, 2020.