General Haig was never Speaker! He as WH Chief of Staff.
Wrong. He was Secretary of State.
Vice President Mike Pence has been called back to Washington from a trip to New Hampshire, according to reports from a Boston NBC station and the New Hampshire Union Leader on Tuesday. The reason was unclear. Pence's spokeswoman, Alyssa Farah, tweeted that "something came up that required the @VP to remain in Washington, DC. It's no cause for alarm."
The line of succession was:
Speaker of the House
Senate Pro Tem
then, Al Haig—so it looked like he was planning to bump off the VP, Speaker and Pro Tem in one decisive maneuver. ;-)