James B. Comey is undeniably the star of the show Thursday, when he comes to the main hearing room in the Hart Senate Office Building for his first public testimony since President Donald Trump fired him as FBI director a month ago. But the eight Republican and seven Democratic senators on the Select Intelligence Committee have highly important roles.

That’s because their questioning will go a long way to shaping whether the national television audience views the congressional investigation of Russian meddling in last year’s election as thorough and serious — or just more partisan posturing.

Here’s a glimpse of the senators by committee seniority, which is the order in which they’ll be called on to ask questions.

Richard M. Burr, R-N.C.

The committee chairman was a national security adviser to Trump’s campaign and never wavered in his support, even though he was in a tight re-election race in a toss-up state. But now, in his third year with the gavel, he’s sending strong signals he’s about running a serious and down-the-middle-investigation — and he’s described himself as “troubled by the timing and reasoning” of Comey’s ouster. 

An appliance salesman who was a House member for a decade before coming to the Senate in 2005, he holds the seat once occupied by Sam J. Ervin Jr., the legendary Democratic chairman of the Watergate Committee in the 1970s. Burr is viewed among the least pretentious senators, a reputation bolstered every time he arrives on the Hill driving his old gray Volkswagen Thing convertible.

Mark Warner, D-Va.

A commitment to being perceived as bipartisan means he gets to call himself vice chairman, not the customary ranking Democrat. And by all appearances, he and Burr have a solid working relationship.

A venture capitalist who made millions in the early years of cell phones, Warner was an activist governor from what he liked to call “the radical political center” and then, very briefly, a presidential candidate before coming to the Capitol in 2009. Since then, he’s sometimes struggled with the Senate’s partisanship and slow, if not gridlocked, pace. But he’s displayed new energy thanks to the Russia probe, which he calls “probably the most important thing I’ve done in public life.”

Jim Risch, R-Idaho

Of all the panel’s members, he’s been the most outspoken defender of Trump, focusing his anger instead on the “weasels” and “traitors” who have leaked stories about the president’s sharing of classified intelligence with the Russians. In the middle of his second term, he’s otherwise among the least visible senators and has a deeply conservative voting record.

Dianne Feinstein, D-Calif.

She was committee chairwoman until three years ago, the last time Democrats were in charge. Recently, she’s been saying that, while she hasn’t seen evidence of collusion between Russia and the Trump campaign, Congress should be just as intent on investigating White House efforts to impede recent investigations.

The oldest current senator, who turns 84 this month, Feinstein is leaning toward running for a fifth full term next year.

Marco Rubio, R-Fla.

His plan last year was to win the presidency or go home, but after he lost the GOP nomination, he changed his mind and won a second Senate term.

He was already one of the Capitol’s most prominent Russia hard-liners, and now he’s eager to use this investigation to lay out for the public the extent of Moscow’s interest in and aptitude for disrupting the U.S. government.

Ron Wyden, D-Ore.

One of the committee’s most combative members, he says it’s “established fact” that Trump actively encouraged Russia “to attack our democracy.”

A senator since 1996 and ranking Democrat on the Finance Committee, he’s blocking the confirmation of the top Treasury Department intelligence official until the department provides any documents it has about financial ties between Russia and Trump associates.

Susan Collins, R-Maine

Her voting record makes her the most centrist Senate Republican, and since January, she’s been among the few in the GOP who have criticized Trump more than sporadically.

She also knows plenty about investigations, having spent four years as chairwoman of the Homeland Security and Governmental Affairs Committee — and having started her life on Capitol Hill interning in 1974 for a House Judiciary Committee member during its debate on  impeaching President Richard Nixon.

Martin Heinrich, D-N.M.

While starting what’s very likely an easy race for a second term next year, he’s been focusing his criticism of Trump on the president’s disclosure to Russian diplomats of highly classified intelligence provided by Israel. He also called Comey’s firing “a direct attack on the integrity and independence of the FBI.”

Roy Blunt, R-Mo.

A former House majority leader, he’s now No. 5 on the Senate GOP leadership ladder — evidence he’s one of the best players of the inside game at the Capitol. He’s talked passionately about Congress doing a thorough Russia investigation, hoping that puts the matter to rest so Congress can focus on tackling the president’s legislative agenda

Angus King, I-Maine

An independent who caucuses with the Democrats, he was governor for two terms, left politics in 2002 and made a comeback by winning his Senate seat a decade later. He’s known for some outside-the-box ideas — including his recent proposal that the Intelligence Committee appoint Comey himself as the staff director for the Russia investigation.

James Lankford, R-Okla.

He has not let Trump off the hook as easily as many conservative senators, pressing the president to release his tax returns and declaring that the Comey dismissal left the American people “needing clarity and deserving an explanation.” He’s halfway through his first term after rising to a junior leadership job during just two terms in the House.

Joe Manchin III, D-W.Va.

As a Democrat from the state that voted most overwhelmingly for Trump last year, he was briefly courted for a Cabinet position last fall and is now the member of the committee with the toughest re-election prospects next year. Defending the panel’s inquiry as “not a witch hunt” was his ready sound bite while back home for the Memorial Day recess.

Tom Cotton, R-Ark.

The youngest current senator, having turned 40 just a month ago, he’s been laying the groundwork for an eventual presidential run. But until then, he says he’s eager to help Trump succeed, vowing to promote the president’s legislative program and urging him to pay less mind to “all of the hair-on-fire, wild-eyed allegations and drama around these inquiries.”

Kamala Harris, D-Calif.

After just five months at the Capitol, following six years as state attorney general, she is working to keep her name in the mix as a potential Democratic national candidate for 2020. And to that end, she’s been one of the president’s tartest critics. 

She was, for example, the first senator to call for Attorney General Jeff Sessions to resign because of questions about his links to Russia.

John Cornyn, R-Texas

Not only is he the majority whip, No. 2 in the GOP chain of command, but he was also the first person to get interviewed and then remove himself from consideration as Comey’s   replacement at the FBI. His leadership job has essentially required him to stick up for Trump, a role he says is made tougher by the president’s “Twitter habit.”