Swann's upcoming autographs sale on April 22 will include this rare manuscript, inked by the hand of 26th US President Theodore Roosevelt himself.
The typed and signed letter, with four holograph corrections, is addressed to Frank T Winslow ("My dear Mr. Winslow").
Roosevelt praises Winslow's prior letter, but states that his own actions have made it difficult to be considered for candidacy.
"I have felt called upon to oppose in the very strongest terms the professional German-Americans," begins Roosevelt.
"And I have not only gained their animosity, but the animosity of practically all American citizens of German descent, who are misled by the professional German-Americans . . . both as to what their attitude should be and as to what mine is."
"The articles that I have written were written with the full knowledge that they would, in all probability, make it impossible to consider me as a candidate," he writes.
The letter originated in Oyster Bay and is dated January 11, 1916.
The Progressive Party nominated Roosevelt for the US presidency in June 1916. While he did not accept, it's thought that this may be the "candidacy" mentioned in his letter.
Roosevelt stated repeatedly that he opposed all "hyphenated Americanism," by which he meant any perceived dividing of allegiance between the US and another nation.
Bearing short tears at the fold, with some loss at the edges, small loss to the bottom right corner and some scattered soiling, the historic letter will auction priced $3,000-4,000.
Unsurprisingly, documents written or signed by former US presidents are among the most coveted and valuable collectible manuscripts on the market.
Earlier this year, a letter by George Washington to his nephew Bushrod in 1778 in which he endorses the idea of the United States Constitution sold for $3.2m at Christie's.
Meanwhile, Paul Fraser Collectibles currently holds another historic and valuable George Washington autograph.
It is for sale as part of our American Presidents Portfolio of exceptionally rare documents and signatures, which you can view here.