What happened in 1814 that allowed the British to commit many more troops in there war with America

"The war was fought in three theaters. First, at sea, warships and privateers of each side attacked the other's merchant ships, while the British blockaded the Atlantic coast of the United States and mounted large raids in the later stages of the war. Second, land and naval battles were fought on the U. S.-Canadian frontier. Third, large-scale battles were fought in the Southern United States and Gulf Coast. At the end of the war, both sides signed and ratified the Treaty of Ghent and, in accordance with the treaty, returned occupied land, prisoners of war and captured ships (with the exception of warships due to frequent re-commissioning upon capture) to their pre-war owners and resumed friendly trade relations without restriction."