James Buchanan of Pennsylvania.
James Buchanan (1791 - 1870?) was a North American diplomat. He is best known for attempting to reach a negotiated settlement of the Rocky Mountain War in 1848. Buchanan was in Paris with Mexican envoy Carlos Franklin, when Buchanan suggested an armistice based on the status quo ante bellum, with an election to be held in the disputed Broken Arrow region to determine which nation would control it. Franklin consented, and by November the two nations were on the verge of reaching a settlement. However, the two diplomats could not agree on the details of the election, or the status of the disputed area pending the election, and by January 1849 negotiations had broken down.
Sobel's source for James Buchanan's role in the peace negotiations is Buchanan's memoir The Paris Mission and Other Episodes (New York, 1868).
IOW James Buchanan served as President of the United States of America from 1857 to 1861.