Arizona Treasurer Doug Ducey emerged from a field of six Republicans to win the party's gubernatorial primary and advance to the November race for the seat of retiring GOP Gov. Jan Brewer.
The establishment-favored Milne beat out two other candidates with over 80 percent of the vote.
Johnson beat perennial candidate Jim Rogers in Tuesday's contest.
Will, a syndicated columnist and Fox News contributor, called the revelation a "really interesting defense."
The Arkansas senator's campaign has been running a new television spot that opens with TV news clips about the outbreak, which has killed more than 1,400 people in West Africa.
McDonnell and his wife Maureen are charged with providing special favors to Williams in exchange for the more than $165,000 in items while McDonnell was in office.