region, while in a later armistice Mexico recognized the Rio Grande as
the boundary. It was in the clear light of these facts that Congress
had passed an act extending the revenue laws of the United States
over the country between the Rio Grande and the Nueces--the very
country in which American soldiers had been slain by an invading
force.

All things considered, Douglas's line of argument was as well
sustained as any presented by the supporters of the war. The absence
of any citations to substantiate important points was of course due to
the impromptu nature of the speech. Two years later,[225] in a
carefully prepared speech constructed on much the same principles, he
made good these omissions, but without adding much, it must be
confessed, to the strength of his argument. The chain of evidence was
in fact no stronger than its weakest link, which was the so-called
treaty of Santa Anna with the President of the Republic of Texas.
Nowhere in the articles, public or secret, is there an express
recognition of the independence of the Republic, nor of the boundary.
Santa Anna simply pledged himself to do his utmost to bring about a
recognition of independence, and an acknowledgment of the claims of
Texas to the Rio Grande as a boundary.[226] Did Douglas misinterpret
these articles, or did he chance upon an unauthentic version of them?
In the subsequent speech to which reference has been made, he cited
specific articles which supported his contention. These citations do
not tally with either the public or secret treaty. It may be doubted
whether the secret articles were generally known at this time; but the
open treaty had been published in Niles' _Register_ correctly, and had
been cited by President Polk.[227] The inference would seem to be
that Douglas unwittingly used an unauthenticated version, and found in
it a conclusive argument for the claim of Texas to the disputed
territory.

Mr. John Quincy Adams had followed Douglas with the keenest interest,
for with all the vigor which his declining strength permitted, he had
denounced the war as an aggression upon a weaker neighbor. He had
repeatedly interrupted Douglas, so that the latter almost insensibly
addressed his remarks to him. They presented a striking contrast: the
feeble, old man and the ardent, young Westerner. When Douglas alluded
to the statement of Mr. Adams in 1819, that "our title to the Rio del
Norte is as clear as to the island of New Orleans," the old ma