War Governors - Great and Not So Great

[hoosier]

In the Mason-Dixon Gazette thread "Virginia's Warner seeks to reclaim captured Confederate flag," Neil has posted a link to a description of a ceremony in which the flag of the 76th Ohio Infantry was returned. The first couple of paragraphs read as follows:

"At Ringgold Gap, Ga., on November 27, 1863, the 1st Arkansas Infantry captured the colors of the 76th Ohio Infantry in a desperate fight, in which eight color bearers of the Ohio regiment were shot down. On September 20, 1916, this flag was returned by the survivors of the 1st Arkansas Infantry during the thirty-eighth annual reunion of the survivors of the 76th Ohio at Newark, Ohio.

"An impressive address by Governor Willis of Ohio was followed by the presentation speech of Governor elect Brough, of Arkansas, whose introductory remarks revealed the special fitness of his participation in this ceremony when he said: 'As the great nephew of Ohio's famous War Governor, John Brough, who ranks with Dix of New York, Curtin of Pennsylvania, and Yates of Illinois as one of the four great War Governors of Northern States, I take pleasure in behalf of the brave troops of the 1st Arkansas Regiment in returning to the brave men of the 76th Ohio the flag captured in the battle at Ringgold Gap, GA, November 27, 1863.'"

I'd like to focus on Mr. Brough's statement identifying his great uncle and three others as "the four great War Governors of Northern States."

I'm wondering - did the designation "War Governor" apply to every person who served as governor of a state during the Civil War, or did it apply only to a select few who had done something special to earn it?

And I'm also wondering - what might the four governors named in the statement have done that would have led Mr. Brough to single them out as being "great," as opposed to all the other War Governors whom he apparently considered to be not so great?