Historians disagree with that position.
The only reason that did not come about is that the war ended a few days before the convention started.
The convention ran from December 15, 1814 to January 6, 1815. News of the signing of the Treaty of Ghent didn't reach the U.S. until February 1815.
I think there is an agenda behind that.
The convention ran from December 15, 1814 to January 6, 1815. News of the signing of the Treaty of Ghent didn't reach the U.S. until February 1815.
February was when the treaty was formally ratified by Congress.
The Treaty of Ghent was signed in December while the Hartford convention was still going on. The British had initiated negotiations in September after a couple of military failures; but it was a US capitulation on the matters of impressment and neutral shipping that ended the war. That change in the US position happened with the consent of the US government and was publicly known before the Hartford convention began.