Student or Learner
An accurate assessment of strategic bombing lies between the extremes of "decisive factor" and "marginally effective adjunct."
What is the meaning of decisive factor and marginally effective adjunct in above sentence?
The first means that bombing is a factor that is decisive (battle-winning, crucial) in the outcome.
The second means that bombing has only a marginal (minimal) effect (effectiveness) as an adjunct to other means.
An accurate assessment is that the effect of bombing lies somewhere between these extremes.