Robert Lansing to Woodrow Wilson

In reply to your note of May 3d, allow me to bring to your attention some further facts for your consideration in connection with the censorship of mails brought to your attention in my note of April 30th. I am not doing this in a controversial spirit or for any other purpose than to have the whole situation laid before you, as I consider it to be of supreme importance. Whatever may be the British facilities for censorship of mails and telegraphs, and whatever may be the stringency of the American censorship of telegraphs, it remains that there is by mail or courier to Mexico and other South American countries an open channel for communication of military information, of credit, and of intrigue, to the countries to the south of us. This, in itself, is important, because we are aware of German intrigue in Mexico, the flocking of thousands of Germans to that country, probable German intrigue in Central America, and also in certain countries of South America. There is, moreover, in these countries, an effort on the part of Germans to build up German trade after the war, which scheme is played up by German newspapers in order to hearten the German spirit at the present time. Again, German raiders have been operating off the South American coasts, and probably obtaining some supplies from German firms in South America. It is very probable that in the near future German submarines may endeavor to undertake similar operations. The censorship of the mails to Latin-American countries at least would assist very materially in preventing or hindering the carrying out of any of the projects mentioned. The matter came up for discussion yesterday at the conference with Mr. Balfour, and he said that the importance of the information obtained from censorship could not be overestimated and could not be fully appreciated in advance.
In the second place, via South America there is direct means of communication with Germany, which seems to me should be cut off. Mail may be sent to South American countries from the United States and transmitted from there by the diplomatic and consular officers of Germany through devious channels of communication; or, I am told by Mr. Balfour, direct to Spain by mail and possibly by cable (he was not sure as to the cable), and thence by wireless from Spain to Germany. Mr. Balfour said that this was a clear channel of communication still open.
I trust you will understand that I am only desiring to inform you fully on what to my mind is a very important matter. If it should turn out that any censorship of mails is imposed by the United States, there would, of course, be no duplication of the censorship by the Entente Powers, as it would be arranged for them to pass mails censored by the United States.