Asked by Judiciary Chairman Sen. Dick Durbin whether the Jan. 6 insurrection was a "one-off" domestic terrorism event, Garland said he didn't think it was, citing comments by FBI Director Chris Wray who has outlined the rise in threat of domestic terrorism in recent years.

Garland said he agreed that we are currently facing "a more dangerous period" than the nation faced when he was overseeing the investigation of the Oklahoma City bombing. He said while he has no inside information about the department's investigation into the Capitol rioters, he said "it looks like an extremely aggressive and perfectly appropriate beginning to an investigation" adding it will be his first priority and first briefing upon his return to the department if he's confirmed.

Asked about the Trump Administration's child separations, Garland said the policy was "shameful" and said he would ensure cooperation from Justice Department into the committee's investigation of the policy.

"I can't imagine anything worse than tearing parents from their children and we will provide all the cooperation we possibly can," Garland said.

Garland was asked whether he will let special counsel John Durham finish his investigation, Garland said he had no information on it but has no reason from what he currently knows to believe Durham should be removed. Garland said it will be among his first briefings upon confirmation as Attorney General.

Garland declined to answer a question from Grassley about whether he will commit to defending the death sentence penalties for certain individuals like the Boston marathon bomber, noting they are pending cases.

Grassley also asked whether Garland had any discussions with Biden about the investigation into Hunter Biden.

"I have not. The president made abundantly clear in every public statement before and after my nomination that the decisions about investigations and prosecutions will be left to the justice department," Garland said. "That was the reason that I was willing to take on this job, and so the answer to your question is no."

-ABC News' Alexander Mallin

Judiciary Chairman Sen. Dick Durbin, D-Illinois, used his opening statement to cast Garland's nomination as "one of the most critical in department history," after summarizing what he described as corruption and abuses under former President Trump and former Attorney General Bill Barr.

Durbin lauded Garland's record both on the federal bench and his time as a Justice Department prosecutor, while outlining the challenges he will face upon his return to the department.  Durbin closed his opening statement by noting that upon his confirmation Garland will be forced to grapple with the Justice Department's sprawling probe of the Jan. 6 insurrection, referencing Trump's role in inciting the mob but stopping short of directly calling on Garland to investigate the former president.

Ranking member of the Senate Judiciary Committee, Sen. Chuck Grassley, R-Iowa, used his remarks to preview what will likely be a priority of Republicans over the next two days -- securing commitments from Garland that upon confirmation he will not seek to fire special counsel John Durham, appointed by his predecessor AG Barr to investigate the origins of the Russia probe, and not interfering with the U.S. attorney in Delaware's ongoing investigation of President Biden's son, Hunter Biden. Grassley also indicated they'll press Garland on investigating Biden's family's financial dealings that he sought to investigate along with Sen. Ron Johnson, R-Wisc., leading up to last year's election.

Garland was formally introduced to the committee by Sen. Chris Van Hollen, D-Md, and Sen. Tammy Duckworth, D-Ill., who gave glowing remarks summarizing Garland's resume, expressing optimism in how he'll be able to tackle the challenges the department and the country currently faces.

-ABC News' Alexander Mallin

Judge Merrick Garland's confirmation hearing for his nomination as the nation's next attorney general is now underway in front of the Senate Judiciary Committee. Garland is expected to face tough questions on everything from combating the nation's domestic terror crisis in the wake of the Jan. 6 insurrection, calls for racial justice and equity in the criminal justice system, restoring the department's independence and how he'll handle politically-sensitive investigations into President Joe Biden's son Hunter and special counsel John Durham's probe into the origins of the Russia investigation.

"The President nominates the Attorney General to be the lawyer -- not for any individual, but for the people of the United States," Garland told the Senate Judiciary Committee in his opening statement according to remarks released over the weekend.

Garland's appearance comes nearly five years after Senate Republicans, including some currently sitting on the committee he'll be in front of today, refused to hold hearings on his nomination by former President Barack Obama to replace the late Justice Antonin Scalia on the Supreme Court.

However, based on remarks from Sen. Chuck Grassley, R-Iowa, who is expected to address their previously stonewalling of Garland's nomination by shifting to attack Democrats for their treatment of Supreme Court Justice Brett Kavanaugh during his confirmation.

"So yes, it’s true that I didn’t give him a hearing. I also didn’t mischaracterize his record. I didn’t attack his character. I didn’t go through his high-school yearbook. I didn’t make his wife leave the hearing in tears. I took a position on hearings, and I stuck to it," Grassley will say.

Garland could also be forced to walk a fine line as he faces potential questions of whether his department should launch investigations into former President Donald Trump for his role in inciting the Jan. 6 riot at the Capitol, after Senate Minority Leader Mitch McConnell recently raised the prospect after his vote against convicting Trump that the ex-president still be held accountable by the criminal justice system.

If confirmed, Garland will bring extensive background experience in the justice system to his role overseeing the department's more than 110,000 employees -- from serving more than two decades in the federal judiciary to his time as a top DOJ prosecutor during the Clinton administration, overseeing major investigations into the Oklahoma City bombing, Unabomber Ted Kaczynski and the Atlanta Olympics bombings.

-ABC News' Alexander Mallin

Merrick Garland, Biden's pick for attorney general, could face tricky political questions during his confirmation hearing before the Senate Judiciary Committee today. In the wake of the Jan. 6 attack on the Capitol, Garland and Democrats are expected to point to Garland's work prosecuting the Oklahoma City bombing as evidence of his ability to investigate and prosecute domestic terrorism.

"If confirmed, I will supervise the prosecution of white supremacists and others who stormed the Capitol on January 6 – a heinous attack that sought to disrupt a cornerstone of our democracy: the peaceful transfer of power to a newly elected government,” Garland will say.

Garland's opening statement also conveys a commitment to equity, saying that upholding the Civil Rights Act remains "urgent" for the Department of Justice. Garland has received ample bipartisan support, ahead of his confirmation hearings before Senate Judiciary Monday and Tuesday, 61 former federal judges and a bipartisan group of more than 150 former Justice Department officials have penned letters in support of Garland's confirmation.

-ABC News' Alexander Mallin and Benjamin Siegel

One hundred and sixty chief executive officers sent an open letter to congressional leadership Wednesday, urging lawmakers to pass "immediate and large-scale federal legislation to address the health and economic crises brought on by the COVID-19 pandemic" on a bipartisan basis.

The letter asks Congress to "to authorize a stimulus and relief package along the lines of the Biden-Harris administration’s proposed American Rescue Plan," perhaps leaving some room for negotiation on what the final package will look like. But the letter makes clear that major business CEOs, including the heads of Morgan Stanley, Visa, United Airlines, BlackRock, Comcast and Google are pushing for relief on the scale of Biden's plan.

"The American Rescue Plan provides a framework for coordinated public-private efforts to overcome COVID-19 and to move forward with a new era of inclusive growth. The country’s business community is prepared to work with you to achieve these critical objectives," the letter says.

Just Tuesday, though, Sen. Mitt Romney, R-Utah, one of the few Senate Republicans who has shown willingness to buck his party, criticized the $1.9 trillion bill in a Wall Street Journal op-ed.

"The $1.9 trillion bill is a clunker. It would waste hundreds of billions of dollars, do nothing meaningful to get kids back to school, and enact policies that work against job creation. The Congressional Budget Office’s recent analysis of the plan found that more than a third of the proposed funding—$700 billion—wouldn’t be spent until 2022 or later, undermining the administration’s claim that the massive price tag is justified for urgent pandemic-related needs," Romney wrote.

Whether the pressure from big business will sway any Republicans in the Senate remains to be seen, but Wednesday morning's messaging from GOP lawmakers is pretty clear: They have no intentions of budging.

-ABC News' Sarah Kolinovsky