citizens, but by foreigners who have resorted
to the United States for the purpose of organizing hostile expeditions
against some of the States of that Republic. The defenseless condition
in which its frontiers have been left has stimulated lawless adventurers
to embark in these enterprises and greatly increased the difficulty of
enforcing our obligations of neutrality. Regarding it as my solemn duty
to fulfill efficiently these obligations, not only toward Mexico, but
other foreign nations, I have exerted all the powers with which I am
invested to defeat such proceedings and bring to punishment those who by
taking a part therein violated our laws. The energy and activity of our
civil and military authorities have frustrated the designs of those who
meditated expeditions of this character except in two instances. One of
these, composed of foreigners, was at first countenanced and aided by
the Mexican Government itself, it having been deceived as to their
real object. The other, small in number, eluded the vigilance of the
magistrates at San Francisco and succeeded in reaching the Mexican
territories; but the effective measures taken by this Government
compelled the abandonment of the undertaking.

The commission to establish the new line between the United States and
Mexico, according to the provisions of the treaty of the 30th of
December last, has been organized, and the work is already commenced.

Our treaties with the Argentine Confederation and with the Republics of
Uruguay and Paraguay secure to us the free navigation of the river La
Plata and some of its larger tributaries, but the same success has not
attended our endeavors to open the Amazon. The reasons in favor of the
free use of that river I had occasion to present fully in a former
message, and, considering the cordial relations which have long existed
between this Government and Brazil, it may be expected that pending
negotiations will eventually reach a favorable result.

Convenient means of transit between the several parts of a country
are not only desirable for the objects of commercial and personal
communication, but essential to its existence under one government.
Separated, as are the Atlantic and Pacific coasts of the United States,
by the whole breadth of the continent, still the inhabitants of each
are closely bound together by community of origin and institutions and
by strong attachment to the Union. Hence the constant and increasing
interco