This statement had not been authorized by the Franklin Pierce administration and was immediately repudiated. Reaction, both at home and abroad, was extremely negative. Marcy later repudiated the report and Soulé resigned. Buchanan, on the other hand, reaped later political benefits in the form of Southern support for his presidential candidacy in 1856.
Whether is was the complication of slavery, language, or some other factor, it was clear that the powerful idea of Manifest Destiny was primarily directed west rather than south.