People talk about the middle of the road as though it were unacceptable. Actually, all human problems, excepting morals, come into the gray areas. Things are not all black and white. There have to be compromises. The middle of the road is all of the usable surface. The extremes, right and left, are in the gutters.

Eisenhower - middle of the road usable surface extremes right and left in the gutters - wist.info quote

Dwight David Eisenhower (1890-1969) American general, US President (1953-61)
Interview (1963-11-05) by William Stringer, “Midroad View at Gettysburg,” Christian Science Monitor
    (Source)

I cannot find an online copy of the source, but it is cited by the Eisenhower Presidential Library, as well as other reliable sources.