From the History of the U.S. State Department government site:
"[Secretary of State Robert] Smith’s major diplomatic mission to improve relations with Great Britain proved a failure. Advised by Madison, Smith entered negotiations with David M. Erskine, the British Minister at Washington. The two intended to stabilize relations between the United States and Britain by restoring neutral trading rights during the Napoleonic War."
"Unfortunately Erskine overstretched his authority, offering too many concessions, and failed to convey British Foreign Minister George Canning’s central requirement for an agreement: that the United States agree not to trade with the French for the duration of Britain’s war with France. This omission doomed the 1809 Smith-Erskine Agreement... ."
"Frustration over the agreement’s failure helped to propel the two countries into the War of 1812."
Commentary concerning Erskine's endeavors:
David Erskine was also mentioned here.