Senator Chuck Grassley.

Iowa Senator Charles Grassley will be at the center of today’s confirmation hearing for the man President Trump has nominated to serve on the U.S. Supreme Court.

Grassley has been a member of the Senate Judiciary Committee since 1981, his first year in the U.S. Senate. He became the panel’s chairman in 2015, when Republicans took control of the Senate.

It means Grassley will be a sort of ringmaster as Supreme Court nominee Neil Gorsuch answers senators’ questions during a hearing that could last for days.

Grassley was at the White House when Trump announced Gorsuch was his pick to fill the vacancy on the nation’s highest court. During an interview that night with Radio Iowa, Grassley called Gorsuch a “principled, mainstream conservative.”

A coalition of progressive groups that go by the name “Why Courts Matter Iowa” argue Gorsuch would be a “threat” to women’s rights. Another group called the “Main Street Alliance of Iowa” says Gorsuch — as a federal judge — has “repeatedly rewarded big business” in his rulings.

Grassley has said he expects “high interest” in his committtee’s hearing this week. Grassley also notes “with television and internet coverage, social media…people everywhere should be able to witness Judge Gorsuch’s testimony.”

The hearing is scheduled to begin today at 10 a.m. Iowa time.

Grassley drew criticism throughout last year for refusing to hold a Judiciary Committee hearing for President Obama’s nominee to fill the vacancy created in February of 2016 when Supreme Court Justice Antonin Scalia died. Democrat Patty Judge, the former Iowa ag secretary and lieutenant governor, ran against Grassley last year, repeatedly saying: “I am the ‘Judge’ Chuck Grassley cannot ignore.” Grassley won reelection with 60 percent of the vote.