Though it was only clear in long hindsight, America had in fact gained a significant point even in fighting a war to such a formally inconclusive end

From the excellent Perilous Fight by Stephen Budiansky, an account of the naval aspects of the War of 1812. Page 359.

But there were consequences of the war so lasting that they would become apparent only when seen across distances of time measured in a century of more. The fact was that regardless of Madison’s ignominious abandonment of America’s positions on impressment and free trade in the negotiations at Ghent, the British never again attempted to press an American seaman and never again attempted to hinder American neutral trade on the high seas. The American legal position that both neutral vessels and neutral goods were immune from seizure by a belligerent slowly became the accepted international norm, and was adopted by Great Britain and other major European powers in the Treaty of Paris in 1856. (Other countries were invited to join as well; the United States ironically refused, objecting to another provision of the treaty abolishing privateering, for fear that this would give large naval powers an advantage over countries such as the United States. But the United States in fact never issued a privateering commission again. The United States also was holding out for the complete abolition of the right of belligerents to capture or destroy enemy civilian property at sea, arguing that the same principles of international law that protect noncontraband civilian property on land should apply on the oceans. That position never has been adopted; international law to this day allows a combatant to capture and take as a lawful prize an enemy’s merchant ships.)

Though it was only clear in long hindsight, America had in fact gained a significant point even in fighting a war to such a formally inconclusive end. Henry Adams implicitly acknowledged as much in noting the cost America had succeeded in imposing on Britain. As a result of trying to maintain her traditional maritime policies, Great Britain had spent £10 million a year waging an ultimately unsuccessful war with a tiny upstart naval power one-hundredth its size. As Adams noted, that meant Britain was spending something like $50,000 a year for each of the impressed Americans it detained in its service. For half as much the Royal Navy could have tripled the pay of all its sailors and obtained the manpower it needed without resorting to impressment at all.

While no one in Britain ever seemed to have made so explicit a calculation, there was widespread recognition that the cost of continuing the fight had indeed become intolerable by late summer and early fall of 1814, largely as a result of the adroit attacks on British seagoing commerce by the American navy and privateers. In the end, the British were as eager to end the war as the Americans were; at Ghent they soon dropped one after another of the “nonnegotiable” demands they had insisted on when the negotiations began. The British had been particularly adamant on retaining northern Maine and establishing the Indian buffer in the northwest. By November 1814 they had conceded both points, and the remaining month of negotiations was spent mainly reducing the agreement to its final wording. The British had been forced to learn a lesson that the United States would later have to relearn for itself in the seemingly one-sided fight it would find itself in a century and a half later in Vietnam: that a determined enemy facing a vastly superior military force can win simply by not losing.

For better or worse, the war’s other great enduring consequence was to end the last real challenge to American sovereignty over North America by its native inhabitants. The Indian tribes who allied themselves with Britain were the war’s greatest losers; the confederacy that united under Tecumseh’s leadership collapsed after his death on the battlefield, and never again would the Indians be able to organize such unified or broad-scale resistance to the relentless press of American western expansion.