“Man is born free, and everywhere he is in chains.”
The Federalists were opposed to the War of 1812 because it would interfere with British trade relations. The Federalists considered England to be a great commercial ally, and since the Federalists were quite in favor of staying wealthy, they didn't want to risk ruining their connections.
At the end of the F & I War, Britain gained control of the Ohio River Valley. Colonists thought that this would allow them to more easily move west. However, the British government had decided to leave all lands West of the Appalachian Mts (according to the Proclamation of 1763) be given to the Indians. This would keep peace in the area and avoid another war between colonists and Indians. The colonists were very angry about this decision. They had fought and died for the land and now were being forced out.
The war between Britain and France was virtually over. King Edward VII visited France in 1903 and won the hearts of the French people by speaking great French and acting graciously everywhere he went. He even gave a famous actress gallant compliments in her native tongue (this kind of thing goes a long way in France). The Anglo-French Entente was ratified in less than a year. The hatred of Edward by Kaiser Wilhelm was another cause (who was his uncle). In truth, the English had already proposed an equivalent entente to Germany in 1899 and 1901, but the Germans had rejected it because they thought it was a ruse. At a dinner with 300 guests in Berlin, the Kaiser made a public statement "He is the devil! You simply cannot comprehend what a Satan he is!" He was irate that he couldn't intimidate or win Edward over, envious of his fame, and worried about what he thought were English designs to "encircle" Germany. But it was for the Belgians, not the French, that Britain allied with France in World War I. Britain had committed to defend Belgium in return for its Continent-wide neutrality. The British intervened to defend them when Germany invaded Belgium without cause (Belgium had done nothing to deserve it) and started massacring civilians.