(SOUND BITE) (English) UNITED STATES CHIEF JUSTICE JOHN ROBERTS, SAYING:

“Senators, I attend the Senate in conformity of your notice for the purpose of joining with you for the trial of the president of the United States. I am now prepared to take the oath.”

As the historic Senate trial of President Donald Trump got underway Thursday, Chief Justice John Roberts – known for avoiding the limelight – entered the ongoing impeachment drama for the first time.

(SOUND BITE) (English) U.S. SENATOR CHUCK GRASSLEY, SAYING:

“…you will do impartial justice according to the Constitution and the laws, so help you God?”

(SOUND BITE) (English) UNITED STATES CHIEF JUSTICE JOHN ROBERTS, SAYING:

“I do.”

(SOUND BITE) (English) U.S. SENATOR CHUCK GRASSLEY, SAYING:

“God bless you.”

Under the Constitution, Roberts is required to preside over the trial, in which all 100 U.S. senators will serve as jurors to decide whether to remove Trump from office — an unlikely result considering his fellow Republicans control the chamber and a two-thirds majority is needed to oust him.

(SOUND BITE) (English) UNITED STATES CHIEF JUSTICE JOHN ROBERTS, SAYING:

“Without objection, so ordered.”

Roberts’ role here is largely ceremonial, as the senators set the rules for the trial and determine its outcome. But he’ll have to keep the trial on track and could be called upon to weigh in on whether certain witnesses should appear.

Though, senators could overrule him if a majority disagrees with any decision he makes.

(SOUND BITE) (English) UNITED STATES CHIEF JUSTICE JOHN ROBERTS, SAYING SEPTEMBER 29, 2005:

“Thank you, Mr. President, for nominating me.”

Appointed by Republican president George W. Bush, Roberts has consistently voted with his fellow conservatives, but he is expected to be careful not to make the Supreme Court look like a tool of one party, says Bill Treanor, Dean Of Georgetown University Law Center.

(SOUND BITE) (English) BILL TREANOR, DEAN OF GEORGETOWN UNIVERSITY LAW CENTER, SAYING:

“I think any chief justice has a legacy – something that they focus on – and for Chief Justice Roberts, I think, the thing that he’s focused on above all is being someone committed to the rule of law. Somebody being apolitical. Starts back during his confirmation proceedings when he talked about justices being like an umpire who calls balls and strikes. We’ve seen it through the decisions – like in the Obamacare case. And I think that’s going to define what he does when he presides over the Senate hearings.”

Back in 2012, he joined the court’s liberal bloc as the deciding vote to uphold the Affordable Care Act – former president Barack Obama’s signature legislative achievement – a ruling Trump has criticized.

(SOUND BITE) (English) REPUBLICAN PRESIDENTIAL CANDIDATE, DONALD TRUMP, SAYING DECEMBER 12, 2015:

“Justice Roberts really let us down, he really let us down. What he did with Obamacare was disgraceful. And I think he did that because he wanted to be popular with inside the beltway or something.”

The rift between the two widened in 2018, when Roberts took the unusual step of issuing a statement defending the federal judiciary after Trump lashed out at judges who had ruled against him.

Elizabeth Wydra, President of the Constitutional Accountability Center, says that Trump and Roberts, while ideologically aligned, clash temperamentally.

(SOUNDBITE) (English) ELIZABETH WYDRA, PRESIDENT OF THE CONSTITUTIONAL ACCOUNTABILITY CENTER, SAYING:

“President Trump and Chief Justice Roberts may come from the same political party, but they are very different people when it comes to how they approach the institutions of Democratic government….Chief Justice Roberts takes very seriously his role as leader of the Supreme Court…So I think he’s going to want to avoid having this impeachment trial become a political circus. Whereas I think President Trump’s desire would be to make this as much of a reality TV event as possible.”

The impeachment trial could be uncomfortable for Roberts, who prefers to fly under the radar even while steering the court in a rightward direction.

(SOUND BITE) (English) ELIZABETH WYDRA, PRESIDENT OF THE CONSTITUTIONAL ACCOUNTABILITY CENTER, SAYING:

“Chief Justice Rehnquist liked to say he ‘did very little and he did it very well’ in the Clinton impeachment trial. I suspect that Chief Justice Roberts is going to be similarly reluctant to get involved in the detailed decisions on how to proceed with the impeachment trial of President Trump. But because there is so much disagreement over this impeachment trial – in a way that there wasn’t even in the Clinton impeachment trial – he may not be able to avoid getting his robe dirty, as it were, in the way that Chief Justice Rehnquist tried to step back from all of those issues.”

On Thursday, Roberts administered the oath to do “impartial justice” to the senators in the chamber, but the trial against the president begins in earnest on Tuesday.