Graham used to be criticized as a "RINO" (Republican-in-name-only) for publicly opposing Trump during the 2016 Republican primary — but now he's one of Trump's staunchest defenders and most loyal surrogates on the Hill.
Graham commanded attention and earned the praise of his fellow Republicans in September during the Judiciary Committee hearings on sexual assault allegations facing Supreme Court Justice Brett Kavanaugh, when he lashed out at his Democratic colleagues and vowed revenge.
"When you see Sotomayor and Kagan, tell them that Lindsey said hello because I voted for them. I would never do to them what you've done to this guy. This is the most unethical sham since I've been in politics," Graham said, referring to Obama-era nominees Sonia Sotomayor and Elena Kagan.
When Kavanaugh told Graham that he'd "been to hell and then some" over the allegations, Graham angrily responded, "This is not a job interview, this is hell."
Previously, Graham told reporters that Democrats can expect their judicial nominees to also face misconduct allegations in the future. "If this is the new norm, you better watch out for your nominees," he said.
Sens. Kamala Harris and Mazie Hirono (also a Democrat on the Judiciary Committee), have recently been accused of anti-Catholic bias for questioning whether judicial nominee Brian Buescher's membership in the Catholic fraternal organization Knights of Columbus would compromise his impartiality on the bench.
Barr himself is Roman Catholic, although not known to be a member of the Knights of Columbus.
As Harris embarks on a book tour ahead of a rumored presidential announcement sometime in late January, all eyes will be on whether she questions Barr's faith during the hearings, and whether she takes advantage of the spotlight to bolster her campaign ambitions.
During Kavanaugh's initial confirmation hearings, Booker took the dramatic step of threatening to release documents purportedly proving Kavanaugh supported racial profiling.
Booker was mocked by some for then declaring, "this is about the closest I’ll probably ever have in my life to an ‘I am Spartacus’ moment" given that the documents had been released that morning.
The comment was a reference to Stanley Kubrick's 1960 film "Spartacus" about an unsuccessful slave rebellion in ancient Rome.
Now that Booker is taking steps towards a 2020 presidential bid, political observers will be watching to see if he creates more "Spartacus" moments for himself during Barr's confirmation process.
Klobuchar, who worked as a district attorney before being elected to the Senate, was lauded for her incisive questioning of Kavanaugh and remaining cool and collected when he turned the questions back on her.
When Klobuchar asked Kavanaugh if he had ever blacked out from drinking, he responded, "you're asking about, you know, blackout. I don't know. Have you?"
When she asked him to confirm his answer was no, he said "Yeah, and I'm curious if you have," to which she calmly responded, "I have no drinking problem, Judge."
The moment earned Klobuchar praise for her tough, but fair approach to questioning Kavanaugh and staying on topic as opposed to grandstanding.
After meeting with Barr on Thursday, Klobuchar told CNN's Anderson Cooper she intends to put the pressure on Barr in next week's hearings.
"I still have concerns relating to his expansive views on executive power & will push more at the confirmation hearing," Klobuchar wrote on Twitter. "He must promise to uphold the Mueller investigation."
Ernst, who has represented Iowa in the Senate since 2014, is one of the first two GOP women to serve on the Committee and will have the opportunity to dive head-first into the work by questioning Barr.
While Ernst has no formal legal background, she served 23 years as a lieutenant colonel in the Iowa National Guard and three years as an Iowa state senator before becoming a US Senator.
Blackburn is one of two freshman Senators to serve on the committee. Before being elected to replace outgoing Sen. Bob Corker in November, Blackburn represented Tennessee's 7th congressional district.
Like Ernst, Blackburn is not trained as a lawyer, but she's worked in government for almost 25 years, beginning her career as director of the Tennessee Film, Entertainment, and Music Commission before being elected to the Tennessee state senate and eventually Congress.
Hawley, 39, defeated Democratic Sen. Claire McCaskill in the 2018 midterm elections, and has extensive experience practicing constitutional law.
Hawley holds a JD from Yale Law School and has worked as a law clerk, an appellate litigator, a law professor, and served as Missouri's attorney general from 2017 until being sworn into the Senate in 2019.
As attorney general, he took part in a lawsuit against the Affordable Care Act with 20 other states and investigated allegations of sexual abuse by Catholic priests in Missouri.
Hawley is staunchly anti-abortion, and has called for "constitutionalist, pro-life judges" to be appointed to federal courts.