key log

plural key logs

1. The log which, if removed, would free up the whole logjam.
2. The key issue or problem, which if (re)solved, would make the current task easy to complete. The issue around which the whole problem revolves.

   Present conditions are "a crisis of confidence. . . . Electric utilities are the key log."

   1938, Col. Leonard P. Ayres, quoted in ""Cheapskate" Counterpoint", in Time magazine, Monday, Jan. 10, 1938

   1 more example

   In a log jam, where everything is at cross-purposes, there is somewhere a key log causing the trouble. The key log in the educational jam is the department, and the things which have caused it to make so much trouble are narrow departmental ambition and excessive striving for reputation through the publication of research.

   1932 December, Homer L. Dodge, “The Improvement of College Teaching”, in The Journal of Higher Education, volume 3, number 9, Ohio State University Press, page 485