In photos: Mandela's life in the spotlight
Four Democratic senators want to know whether White House deputy chief of staff Bill Shine is breaking ethics laws as he continues to get paid millions in bonuses by Fox News, his former employer.
"Investors like certainty," Kenneth Duberstein told CNBC. "Any perceived foreign or domestic uncertainty creates problems for the markets."
Butina is charged with conspiracy and failing to register as a foreign agent. She and federal prosecutors filed a joint motion in U.S. District Court in Washington to ask a judge to set a date for a change-of-plea hearing as soon as possible.
It is expected that Prime Minister Theresa May will now attempt further negotiation with the European Union.