What had nearly been considered indiscriminate bombing?
Although official German air doctrine did target civilian morale, it did not espouse the attacking of civilians directly. It hoped to destroy morale by destroying the enemy's factories and public utilities as well as its food stocks (by attacking shipping). Nevertheless, its official opposition to attacks on civilians became an increasingly moot point when large-scale raids were conducted in November and December 1940. Although not encouraged by official policy, the use of mines and incendiaries, for tactical expediency, came close to indiscriminate bombing. Locating targets in skies obscured by industrial haze meant they needed to be illuminated "without regard for the civilian population".
The US Congress was urged to create the exemption by proponents of a conservation plan on San Bruno Mountain, California that was drafted in the early 1980s and is the first HCP in the nation. In the conference report on the 1982 amendments, Congress specified that it intended the San Bruno plan to act "as a model" for future conservation plans developed under the incidental take exemption provision and that "the adequacy of similar conservation plans should be measured against the San Bruno plan". Congress further noted that the San Bruno plan was based on "an independent exhaustive biological study" and protected at least 87% of the habitat of the listed butterflies that led to the development of the HCP.