Possible Clues:

• Board mtg. exec
• First part of POTUS: Abbr
• The "P" of POTUS, for short
• C in C
• G.W., at first
• Marine One rider (Abbr.)
• Wash. title
• Three-term title for 22-Across: Abbr
• Oval Office title: Abbr.
• Corp. V.I.P.