Campaign advertising

Democratic presidential candidate businessman Tom Steyer speaks during a presidential forum at the California Democratic Party's convention Saturday, Nov. 16, 2019, in Long Beach, Calif. (AP Photo/Chris Carlson)

FILE - In this Feb. 8, 2018 file photo, the logo for Twitter is displayed above a trading post on the floor of the New York Stock Exchange. In a policy published Friday, Nov. 15, 2019 Twitter said it is banning ads that contain references to political content, including appeals for votes, solicitations of financial support and advocacy for or against political content. The ban also includes any ads by candidates, political parties, elected or appointed government officials. (AP Photo/Richard Drew, File)

Roger Stone, a longtime Republican provocateur and former confidant of President Donald Trump, waits in line at the federal court in Washington, Tuesday, Nov. 12, 2019. (AP Photo/Manuel Balce Ceneta)

Former White House strategist Steve Bannon arrives to testify for the federal trial of Roger Stone, at federal court in Washington, Friday, Nov. 8, 2019. (AP Photo/Al Drago)

CORRECTS SPELLING OF LAST NAME TO KHALID INSTEAD OF KAHLID - Safiya Khalid speaks at a candidates forum at Geiger Elementary School in Lewiston, Maine. Lewiston, a city in Maine that is home to thousands of African newcomers, elected Khalid, a Somali American to its city council after she soundly defeated a fellow Democrat on Tuesday. (Andree Kehn/Sun Journal via AP)

FILE - In this May 29, 2019, file photo, Alaska Gov. Mike Dunleavy speaks to reporters in his office at the state Capitol in Juneau, Alaska. A fight is brewing over whether Dunleavy, a Republican who took office in Dec. 2018, should be recalled. Critics say he’s incompetent and has recklessly tried to cut spending while supporters see a politically motivated attempt to undo the last election. (AP Photo/Becky Bohrer, File)

FILE - In this Sept. 5, 2018, file photo Twitter CEO Jack Dorsey testifies before the House Energy and Commerce Committee in Washington. "While internet advertising is incredibly powerful and very effective for commercial advertisers, that power brings significant risks to politics, where it can be used to influence votes to affect the lives of millions," Dorsey said Wednesday, Oct. 30, 2019, in a series of tweets announcing Twitters new policy of banning all political advertising from its service. (AP Photo/Jose Luis Magana, File)

FILE - In this Feb. 2, 2019 file photo Virginia Gov. Ralph Northam, left, gestures as his wife, Pam, listens during a press conference in the Governors Mansion at the Capitol in Richmond, Va. Northam is actively campaigning for Democratic legislative candidates ahead of Election Day (AP Photo/Steve Helber, File)

Democratic presidential candidate South Bend, Ind., Mayor Pete Buttigieg listens to a question during a campaign stop, Thursday, Oct. 24, 2019, in Nashua, N.H. (AP Photo/Mary Schwalm)