Many people in the years since it happen had wondered what would happen in the magazine at Fort McHenry didn't explode. Or if General Ross hadn't fallen in the Battle of North Point, leaving command of the British Army to Colonel Arthur Brooke.
Some have said that with the support of fleet that destroyed Baltimore, General Ross would have delivered the knockout blow to the United States. But Colonel Brooke saw the American force under General Samuel Smith had withdrawn from the city and good order and he was out number at least 2 to 1. With the Americans outnumbering him Colonel Brooke was unwilling to commit his forces on what would been the knockout blow to the United States. So British Admiral Alexander Cochrane turned his guns loose on Baltimore.
Over a period of 17 hours Cochrane's fleet blasted Baltimore. Some believed Cochrane would kept bombarding the city if not for the power magazine on HMS Tonnant[1] exploded about noon on the 15th.
But one thing is not in doubt, the bombardment of Baltimore by the British so scared the United States, that they would never allowed it to happen again. And after the Treaty of Ghent, the American nation when on build a military that would defend her, and as the years passed, give her victory after victory, sometimes against great odds, but she would be given a victory.
[1] This is the ship that Francis Scott Key was on.