Chief Justice John Roberts will play a key role in President Donald Trump's impeachment trial in the Senate.
The 64-year-old George W. Bush appointee will serve as the presiding officer in what will be only the third impeachment trial in U.S. history.
Roberts, a longtime establishment Republican who has at times found himself at odds with the president, has broad discretion to shape the proceedings under longstanding Senate rules. But it's likely that Roberts, who has sought to limit the appearance of partisanship in the federal judiciary, will seek to minimize his role.
The Senate's impeachment rules from former President Bill Clinton's 1999 impeachment call for the chief justice to "direct all the forms of proceedings while the Senate is sitting for the purpose of trying an impeachment, and all forms during the trial not otherwise specially provided for."
The rules say the chief justice "may rule on all questions of evidence."
Under those rules, an adaptation of which is expected to apply to the coming impeachment, a majority of senators may overrule the chief's decisions. The GOP has a 53-member Senate majority.
The most pressing questions Roberts could face might concern potential prosecution witnesses.
Sen. Chuck Schumer of New York, the top Democrat in the Senate, has pushed to subpoena White House chief of staff Mick Mulvaney and former national security advisor John Bolton, among others, to appear for questioning. Senate Majority Leader Mitch McConnell, R-Ky., has so far rejected Schumer's demands.
The last chief justice to preside over an impeachment trial, the late William Rehnquist, took a largely passive role in overseeing the trial, generally leaving procedural questions to the senators. Roberts, who clerked for Rehnquist in the early 1980s before joining the Reagan administration, has given no indication he plans to take a more interventionist role.
McConnell said this month that he is coordinating with Trump and the White House counsel on the impeachment procedures, infuriating Democrats.
"I'm going to take my cues from the president's lawyers," McConnell said in an interview with Fox News personality Sean Hannity.
The trial, expected to begin in January, comes as the Supreme Court considers a slate of high-profile disputes, including three cases involving Trump's effort to shield his financial records from local prosecutors in New York as well as multiple Democratic-led congressional committees. Those cases will be heard in late March or early April.
The top court has already heard major cases over LGBT worker rights, the Second Amendment, and the Obama-era program that shields the young migrants known as Dreamers this term. It will hear cases over a Louisiana abortion regulation and the constitutionality of the Consumer Financial Protection Bureau in March.
The court is expected to release its opinions in those cases in June, as the 2020 presidential race is in full swing.
Roberts will likely split his days between hearing cases in the morning and attending to impeachment during the afternoon, as Rehnquist did. Clinton's impeachment trial, which ended in February of 1999, lasted about five weeks.
Despite the fact that Roberts is a Republican, some conservative allies of the president have called on him to recuse himself from the proceedings. Roberts, like the other justices on the nine-member court, generally avoids expressing political views outside the bounds of the court's formal business. But he has at times pushed back on the president.
For instance, when Trump accused a federal judge in California of being an "Obama judge" last year, Roberts retorted in a statement: "We do not have Obama judges or Trump judges, Bush judges or Clinton judges."
"What we have is an extraordinary group of dedicated judges doing their level best to do equal right to those appearing before them," Roberts wrote.
Trump has regularly berated Roberts on Twitter since 2012 over Roberts' vote to uphold parts of Obamacare that year.
The chief justice has written the majority opinions in the most significant 5-4 decisions of Trump's presidency.
In June of 2018, Roberts wrote the decision for the court that upheld a version of Trump's travel ban that applied to several Muslim-majority countries. This June, he ruled against the president, writing the decision in a case that barred the Trump administration from adding a citizenship question to the 2020 census.
Roberts did not respond to a request for comment submitted to a Supreme Court spokesperson.