Oklahoma Gov. Kevin Stitt is expected to appoint Alan Armstrong, chairman of Williams Companies, to the U.S. Senate seat currently held by Sen. Markwayne Mullin, according to sources familiar with the process. The move comes as Mullin advances in the confirmation process to replace Kristi Noem as Department of Homeland Security under President Donald Trump. On Thursday, The Senate Homeland Security and Governmental Affairs Committee advanced Sen. Mullin’s nomination in an 8 to 7 vote, setting up a vote before the full chamber as early as this week. If appointed, Armstrong would serve until the next election, when Oklahoma voters...