Edward "Mackie" MacDougan is the commander of the EAS Vesta.
During the Battle of Proxima III, Captain MacDougan broke radio silence and opened communications with Captain John Sheridan. Following this conversation, MacDougan refused to engage the Whitestar fleet, feeling that it would be an action in support of illegal orders.
As a result, Captain Trevor Hall promoted Commander William Philby and ordered him to take command of the Vesta. He preceded to bring the Vesta into the fight, but only for a short time. The crew of the Vesta "postponed" Philby's promotion, and returned command to MacDougan. He ordered the Vesta to stand down, and declared his ship non-hostile to the Whitestar fleet. Later he would join up with Sheridan's forces and participate in the latter battles of the war.  After his defection, Clark loyalists in Earthforce briefed all starship Captains that MacDougan and his crew had been executed and that a Minbari crew had been put in charge of the Vesta. His voice was enough to convince Captain Leo Frank of the EAS Cadmus to stand down.