Polk, the trumped up Mexican War, Massive Deficits and One Term
Mahablog has mentioned Lincoln's anti-Mexican War speeches.
Here is the full text of Lincoln's speech.
Here is a direct link to the Congressional Globe, which should be pretty near the page where the speech in question is given. All the stuff from TIFF/Page 141 on is pretty neat, talking about Polk laying waste to the traditions of Washington and Jefferson.
Representative Stewart Of Penssylvania had this to say, on the house floor, of Polk's men and what they can do with their war "Let them sport their pleasure-boat in the rivers of tears shed by orphan children and their widow mothers"