The blacklist was the last straw which provoked the retaliatory legislation. But, alone of the seemingly unadjustable disputes pending between the United States and Great Britain, it was on the blacklist issue that the latter had an unanswerable defense. The British stand left official Washington's complaint bereft of foundation under international law. The only ground on which the American protest could be justified was by contending that the blacklist violated international comity. In other words, if it was not illegal--there was no doubt of its legality--it was an incivility.
There had been the usual diplomatic exchange between the two governments on the subject prefacing a lengthy communication sent by Lord Grey--the new title of the British Foreign Secretary upon his promotion to the peerage--on October 10, 1916. Therein he repeated that the blacklist was promulgated in pursuance of the Trading with the Enemy Act (a war measure explained in a previous volume), and was a piece of purely municipal legislation. Moreover, the American Government was assured, "the Government of Great Britain neither purport nor claim to impose any disabilities or penalties upon neutral individuals or upon neutral commerce. The measure is simply one which enjoins those who owe allegiance to Great Britain to cease having trade relations with persons who are found to be assisting or rendering service to the enemy."
Nor were the steps taken confined to the United States:
"With the full consent of the Allied Governments, firms even in Allied countries are being placed on the statutory list, if they are firms with whom it is necessary to prevent British subjects from trading. These considerations may, perhaps, serve to convince the Government of the United States that the measures now being taken are not directed against neutral trade in general. Still less are they directed against American trade in particular; they are part of the general belligerent operations designed to weaken the enemy's resources."
The burden of the note was that Great Britain maintained the right, which in the existing crisis she also deemed a duty, to withhold British facilities from those who conducted their trade for the benefit of her foes. This right Lord Grey characterized as so obvious that he could not believe the United States Government seriously contested the inherent privilege of a sovereign state to exercise it except under a misconception of the scope and intent of the measures taken. It would appear that the American Government gracefully surrendered, by default, its earlier contention that Great Britain had no right to forbid her subjects from trading with American firms having Teutonic affiliations.