Causes of the War of 1812: The Reasons Behind the Second American Revolution

This painting of the Battle of Queenston Heights depicts the unsuccessful American landing on October 13, 1812.

Why did James Madison ask Congress to declare war on Great Britain in 1812? Why did the United States invade Canada? What were the causes of the War of 1812?

The War of 1812 is one of the strangest and yet most controversial wars in American history. What were the causes of the War of 1812? Why is the War of 1812 sometimes called the second American Revolution? Why did the United States invade Canada? These are the questions, which this article will attempt to answer.

US and British Interests Collide — Setting up War of 1812

The British Empire formally recognized the independence of the United States of America with the Treaty of Paris in 1783, but tensions remained between the Mother Country and her offspring.

For its part, the United States wished to expand into the western territories and establish free trade with Europe (including Britain’s enemy, France).

The British Empire welcomed trade with her former North American colonies (so long as the terms of the trade were advantageous), but in 1812, the British were locked in a brutal and ongoing struggle with France. Indeed, the British had fought a series of wars with France, including the French and Indian War and the American Revolution. Britain therefore used its naval power to obstruct France’s international trade. This meant seizing American trade vessels.

What’s more, Britain needed manpower for its Royal Navy and could ill afford the desertions its navy was suffering. And many of those deserting seamen were fleeing to American ships. Britain therefore justified both the seizure of American trade vessels and the impressment of American seamen (including and especially suspected British deserters) into His Majesty’s Navy.

Moreover, the British Empire hoped to restrain US expansion into the western frontier. It was simply not in the best interests of Britain’s remaining North American colony, Canada, for the United States to expand unimpeded to the Pacific Ocean. Accordingly, Britain and Canada supported Indian tribal nations in their resistance to US expansionism. This included an alliance with the charismatic Indian leader Tecumseh.

Congress Declares War on Great Britain

President James Madison asked the United States Congress to declare war on the British Empire. In his war message, Madison took principal aim at Britain’s complete disregard of US sovereignty on the high seas:

British cruisers have been in the continued practice of violating the American flag on the great highway of nations, and of seizing and carrying off persons sailing under it, not in the exercise of a belligerent right founded on the law of nations against an enemy, but of a municipal prerogative over British subjects.

Not only had Britain defiantly disregarded the American flag on the high seas, but it was also violating US territorial sovereignty. Madison explained:

British cruisers have been in the practice also of violating the rights and the peace of our coasts. They hover over and harass our entering and departing commerce. To the most insulting pretensions they have added the most lawless Proceedings in our very harbors, and have wantonly split American blood within the sanctuary of our territorial jurisdiction….

Under pretended blockades, without the presence of an adequate force and sometimes without the practicability of applying one, our commerce has been plundered in every sea, the great staples of our country have been cut off from their legitimate markets, and a destructive blow aimed at our agricultural and maritime interests….

President Madison also held Britain responsible for “warfare just renewed by the savages on one of our extensive frontiers–warfare which is known to spare neither age nor sex and to be distinguished by features peculiarly shocking to humanity.”

With the respect to the frontier, historian Bevin Alexander explains: “The conviction grew without the West that the frontier could enjoy security only by expelling the British from Canada and annexing the entire region to the United States.”

For these reasons, Madison requested – and Congress approved – a declaration of war on the British Empire.

The War of 1812 would be last for close to three years, and would prove extremely difficult for the young United States. Though it ended in more or less a stalemate, the United States established itself as a worthy member of the family of nations, captured a newfound nationalism, and would never again face such an overt threat to its sovereignty.


  1. 1812: The War That Forged a Nation by Walter Borneman
  2. How America Got it Right by Bevin Alexander