one. Such ports as Rotterdam, Amsterdam, and Copenhagen are
just as useful to Germany for purposes of commerce as are Hamburg and
Bremen, and, in fact, a special commercial arrangement with Rotterdam
has made that city practically a port of Germany since 1868. These
considerations show how ineffective would be a blockade of the German
coast which did not also comprehend the coast of Holland and Denmark.
Germany could still conduct her commerce through these neighbouring
countries. And at this point the great difficulty arose. A blockade is
an act of war and can be applied only to a country upon which war has
been declared. Great Britain had declared war on Germany and could
therefore legally close her ports; she had not declared war on Holland
and Denmark, and therefore could not use the same measure against those
friendly countries. Consequently the blockade was useless to Great
Britain; and so, in the first six months of the war, the Admiralty fell
back upon the milder system of declaring certain articles contraband of
war and seizing ships that were suspected of carrying them to Germany.

A geographical accident had apparently largely destroyed the usefulness
of the British fleet and had guaranteed Germany an unending supply of
those foodstuffs without which she could not maintain her resistance for
any extended period. Was Great Britain called upon to accept this
situation and to deny herself the use of the blockade in this, the
greatest struggle in her history? Unless the British fleet could stop
cargoes which were really destined to Germany but which were bound for
neutral ports, Great Britain could not win the war; if the British fleet
could intercept such cargoes, then the chances strongly favoured
victory. The experts of the Foreign Office searched the history of
blockades and found something which resembled a precedent in the
practices of the American Navy during the Civil War. In that conflict
Nassau, in the Bahamas, and Matamoros, in Mexico, played a part not
unlike that played by Rotterdam and Copenhagen in the recent struggle.
These were both neutral ports and therefore outside the jurisdiction of
the United States, just as Rotterdam and Copenhagen were outside the
jurisdiction of Great Britain. They were the ports of powers with which
the United States was at peace, and therefore they could not be
blockaded, just as Amsterdam and Copenhagen were ports of powers with
which Great Britain was now at peace.