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Pan American War (1846-1852): Wellington's Walk
... Britain has a lot of Napoleonic Wars veterans still healthy and kicking to ship overseas, assuming that Canada isn't overrun immediately, the US will be claiming 'redcoats imba, Wellington hax' shortly.

Yeah, about that...

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PAN AMERICAN WAR (1846-1852):

Wellington's Walk:

The nail in the coffin for America's part in the war was the event that became known as "Wellington's Walk." From his headquarters at La Citadelle above Quebec City, the Duke of Wellington laid his plans for a campaign that would sweep south from the recaptured city of Montreal and aim straight at the economic and industrial heart of the nation. The plan was relatively simple; keep the coast under bombardment and enforce a blockade while an army continuously streams down from Montreal to strike at American cities on their way to Washington D.C.

The first crucial battle was the Battle of Plattsburgh which was a resounding British victory. While the Americans retreated south, a secondary force struck out from Kingston and took Watertown, New York. This secondary force's aim was to serve as a distraction and to threaten Syracuse, thereby drawing away American troops from the Niagara region. This would also help prevent Wellington's army from being completely cut off. Sporadic skirmishes occurred until the two sides put stakes in the Battle of Schenectady. The Americans knew that if the British and Canadians crossed the Mohawk River, they would need to evacuate Albany and that would leave New York City vulnerable. Wellington for his part desired secure access to the Hudson with which to quickly ferry troops down to New York City.


The Battle of Eccles Hill, May 25, 1849.
The precursor to the Battle of Plattsburgh that would happen a few weeks later.

The Battle was a vicious one, but the inexperienced troops were no match for the Duke and his hardened veterans. English and French Canadians, British, and Native soldiers came together and won the battle for the Crown, though at a great cost. When British forces walked into Albany two days later, they found the town nearly deserted. Britain now had control of the upper Hudson River.

The Americans made their next major stand at the Battle of Poughkeepsie. However, with British pressure on New York City, new riots had broken out and troops had to be recalled to help restore order [1]. This resulted in less troops being available on the line which allowed for a partial British encirclement. The battle quickly turned into a retreat. The Americans continued to retreat south, only offering the British token resistance. Some feared a trap, but the British held firm along the west bank of the Hudson and Lake Champlain, limiting the possibility of surprise. They were also helped by the fact that large parts of this area were essentially rural wilderness.


The Astor Place Riot, May 10, 1849.
This event would be the spark that causes unrest and violence in New York City. Some would even come to blame this riot for the loss of New York to the British that summer.

With New York City rioting, the British used that moment to their advantage and launched an assault on the city and its environs. By this point, Wellington had reached Yonkers. Stuck between the two forces, it was an utter rout. Joined together, a largely naval occupying force was left behind while the rest of the forces made a beeline for Philadelphia. It became clear to many Americans at this point that Washington D.C. was the objective and that naval forces and marines would wait until Wellington's land forces were in the area to strike.

These fears led to the Americans redirecting forces to Philadelphia. This is exactly what the Duke and his commanders had counted on. While thinking that the Royal Navy and British Marines were simply holding position, they were lured into a false sense of security. Once British spies caught wind of additional troops headed to Wilmington and Philadelphia, the fleet that had been blockading Chesapeake Bay took that as their cue to begin the attack on Washington D.C. Just as in the War of 1812, it was a British victory only there was no storm to save Washington this time. The city was burned and looted for three days and most political and industrial buildings were burned or leveled.


The ruins of the White House

With their capital in ruins, Baltimore under siege, and the risk of encirclement and utter annihilation in Philadelphia prompts many Americans to sue for peace. The North American theatre of the Pan American War has come to a close late in the year of 1849, and at great cost and embarrassment to the United States.

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[1] The Astor Riot happened OTL but since it happened in wartime ITTL, I could see this causing a lot more unrest and leading to something bigger. This event would come to be seen by many Americans as a sort of "we wouldn't have lost NYC and could've halted the advance earlier if this hadn't happened" moment in history.

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