The country would have been considerably smaller if we’d followed the advice of New Englanders. The men of New England declared that Britain's terms to end the War of 1812 were just and liberal and advised that granting them would be political wisdom. These same folks threatened secession if Jefferson followed through with the purchase of the Louisiana territory from France."

Here are Britain's demands to end the War of 1812: 

America would yield all the Northwest including Michigan, Wisconsin, Illinois, parts of Indiana and one third of Ohio as a perpetual Indian Territory and barrier between Canada and the US. 

Renounce the right to keep armed vessels on the lakes and military posts on the shores and relinquish a considerable portion of Maine to the British. 

Later New England would fight to keep Texas out of the Union but, once in, refused to let Texas go...