House Democratic leader Nancy Pelosi stressed that the "public has a right to know, and no one is above the law in terms of our having access to that information."
At least one demonstration is planned in every state in the U.S.
Whitaker replaces Attorney General Jeff Sessions, who was asked to resign as the country's top law official by President Donald Trump.
Protesters held up neon letters spelling out "Protect Mueller" after Democrat lawmakers sounded the alarm that Attorney General Jeff Sessions's resignation could spell trouble for special counsel Robert Mueller's investigation.
Jeff Sessions's temporary replacement as attorney general has criticized the Mueller investigation for widening the scope of its inquiries.
"At your request, I am submitting my resignation," Sessions wrote in his resignation letter.
David Dratch, 23, could face up to five years in prison and a $250,000 fine if convicted.
"The world will be diminished if journalists aren't able to go and travel and to report honestly conditions in differing countries," Attorney General Jeff Sessions said.
"Actions that could happen would be a lifetime ban if someone is entering the U.S. for work related to the marijuana industry," Michael Collins, interim director at the Drug Policy Alliance's Office of National Affairs, told Newsweek.
"If we don't see something happen in 2019, almost all of us will be takeout targets for Canadian players."
"We in California will continue to do what's right for our residents," said Democratic senator Scott Wiener.
Matt Whitaker is chief of staff to Attorney General Jeff Sessions, and if President Donald Trump pulls the trigger on Rod Rosenstein, Whitaker will replace him.
Trump, in an interview with Hill.TV, said Sessions wanted to be attorney general, but that he "didn't see it."
Unions and organizations representing judges were quick to criticize Sessions's comments on Monday.
President Donald Trump told reporters Friday that he wanted Attorney General Jeff Sessions to investigate the identity of the senior administration official behind the anonymous New York Times op-ed essay published this week as he considered legal action against the paper.
Ben Sasse was responding to the president's latest attack on the Department of Justice.
Poll conducted by Washington Post and ABC see's Trump disapproval hits new high.
The president has openly attacked the attorney general.
The president previously backed the plan but will reportedly wait until after the midterm elections.
Clue: It's not an F.
President Donald Trump has hit out at U.S. Attorney General Jeff Sessions over his decision to recuse himself from special counsel Robert Mueller's investigation into Russian interference in the 2016 election.