Lyman Cutlar was an American farmer who, in 1859, had squatted on the San Juan Islands near Seattle. In June, he saw a large black pig eating his potatoes and shot it dead.

The pig, it turned out, was owned by Charles Griffin, a ranch manager employed by Britain’s Hudson Bay Company.

Since the sovereignty of the San Juan Islands between the US and the United Kingdom had never been resolved, the financial dispute soon escalated to a military one.

The Pig War, as it was known, began with the US sending 66 soldiers to the area surrounding the ranch on the warship USS Massachusetts and grew to where the British sent five warships that housed “more than two thousand men and seventy cannons.”

Luckily, cooler heads prevailed. Ordered to attack the badly outnumbered Americans, British Rear Adm. Robert Baynes refused, saying that “to engage two great nations in a war over a squabble about a pig” was foolish.

It’s said the Pig War passed without a shot being fired, though Kevin Lippert, author of the entertaining new history “War Plan Red,” notes that’s not completely true.

“To be accurate,” he writes, “one shot was fired, and one life lost: that of the anonymous pig.”

Farce of 1812

For many, the biggest surprise about a book documenting the history of military conflicts between the US and Canada is that it exists at all. But according to Lippert, not only do our two countries have an intricate history of conflict, but each nation has drawn up once-secret plans for the invasion of the other.

By 1791, the provinces of Upper and Lower Canada had been created with often ill-defined US borders, and many here saw them as the rightful possessions of the United States.

So during the War of 1812, those who craved Canada saw opportunity, especially since the American military presence was twice the size of Britain’s.

“What nobody foresaw, though,” Lippert writes, “was that American troops soldiered like extras from a Laurel and Hardy film.”

Revolutionary War hero Gen. William Hull was assigned to lead the approach to Canada from Detroit. Once there, he sent a schooner ahead carrying not just supplies, but the US’s secret attack plans to capture a Canadian fort.

But when the US officially declared war on Britain, the letter sent to inform Hull didn’t reach him in time. Hull had sent the schooner directly toward British warships, delivering the US war strategy right into enemy hands.

When 2,000 American troops marched toward Quebec City — toward a battle thought so easily winnable that President Thomas Jefferson said that taking Quebec was just “a matter of marching” — the British were waiting, along with Native Americans they had enlisted to fight on their side.

Hull, who had a fear of the natives he regarded as “savages,” surrendered without a shot having been fired and was later “court-martialed for cowardice and neglect of duty.”

Attempts to take Canada continued to no avail, including one by a force of 500 that marched into Quebec for a late-night sneak attack but, confounded by the darkness, wound up firing on each other.

Pork and beans war

Then came 1839, when, for the only time in our history, Lippert writes, an American state went to war with a foreign country.

Maine had long been engaged in disputes with the Canadian province of New Brunswick over the rights to cut down trees on the border between the two regions.

Officials sent a volunteer militia to “confiscate the equipment of any New Brunswick lumberjack they could find cutting ‘their’ trees.”

But the militia were quickly captured by the Canadians, who “transported them, in chains, to a barracks in Woodstock, New Brunswick.”

The escalation that followed came to be known as the Pork and Beans War, “in honor of the lumberjacks’ beloved favorite meal.” The US Congress “authorized a force of fifty thousand men and $10 million under the command of General Winfield ‘Old Fuss and Feathers’ Scott.”

Hostilities faded quickly, though, and once again, no shots were fired. The US and Canada redrew the border “in a way that gave more land to the States than to Canada,” a move justified by the Canadians because, they said, “the whole territory we were wrangling about was worth nothing.”

In 1858, a group of Irish Catholic Americans founded the Fenian Brotherhood. Hoping to force the British to withdraw from Ireland, they hatched a simple plan — to seize Canada as a “hostage.”

While the Fenians had significant US support, including from Secretary of State William Seward, they “misread the equation on the northern side of the border.”

Expecting support from the Canadian citizenry, they failed to realize that “most Canadian Irish were Protestants from Northern Ireland, not Catholics.”

In the summer of 1866, the Fenians sent “one thousand men in canal boats from Buffalo to Fort Erie, Ontario, part of a planned five-pronged invasion of Canada from New York, Illinois, Wisconsin, Vermont and the St. Lawrence River.”

The Fenians surprised the Canadians with an easy victory in Ridgeway, Ontario, before being driven back across the border. “Emboldened” by their one victory, the Irish spent the next five years conducting sneak attacks on Canadian targets, including “planting an Irish flag in the Canadian village of Pigeon Hill.”

By 1870, the Fenians had “amassed an astonishing arsenal of fifteen thousand weapons and three million rounds of small-arms ammunition.”

But just as they prepared to launch a larger invasion, President Ulysses S. Grant, supposedly with the Fenians in mind, “issued a proclamation upholding the US Neutrality Act of 1818, which meant the government would stop looking the other way at the Fenians’ Canadian incursion.”

The Fenians tried one last time in 1871, “invading” Manitoba with just 40 men before the Americans corralled them back.

Defense scheme No. 1

While skirmishes between the two nations subsided, the threat of such did not. In 1921, at a time of major tension between the US and Great Britain over that country’s $22 billion war debt, a Canadian lieutenant colonel named James “Buster” Brown devised Defence Scheme No. 1, “a plan against an imagined war with the United States, Europe, Japan, or a combination.”

Among [Canadian Lt. Col. James Brown’s] insights: that the men of Vermont were “fat and lazy but pleasant and congenial.”

In gathering the intelligence he needed to formulate the plan, Brown “seems to have been inspired by Buster Keaton, as he and four fellow officers under his command donned disguises, loaded into their Model T, and began an espionage mission along the Canada-New England border” while Brown took pictures and notes.

Among his insights: that the men of Vermont were “fat and lazy but pleasant and congenial”; that rural American women “appear to be a heavy and not very comely lot”; and that “if [Americans] are not actually lazy, they have a very deliberate way of working and apparently believe in frequent rests and gossip.”

The plan he eventually devised called for quick sneak attacks on weak US targets, including crucial infrastructure such as bridges and train tracks, to slow the US down until the British cavalry arrived.

While Brown had detractors who saw the plan as “harebrained at best,” others thought it had potential, especially since the US was weakened, just having emerged from the costly and deadly World War I. But Brown’s successor, Andrew McNaughton, thought it so ridiculous that he “ordered all copies of the scheme, including Brown’s recon notes, burned.”

War plan red

A decade later, believing that war with Britain was still possible, the War Plans Division of the American War Office created War Plan Red, a plan for an eventual war with Great Britain that would counter “a Canada-based invasion of the Great Lakes and manufacturing cities of the Northeast” with “a rapid counterinvasion of Canada.”

The American plan was devised by people with no knowledge of Brown’s plan, yet was “an eerie mirror image” of Brown’s scheme, “with invasions along almost identical paths.”

One developer of the plan was famed aviator Charles Lindbergh, who “flew covertly as a spy to the west shore of Hudson Bay to investigate the possibility of using seaplanes for warfare and seek out points of low resistance as potential bridgeheads. He recommended the bombing of industries in Canada and the use of chemical weapons, supposedly outlawed by the Geneva Protocol of 1925.”

War Plan Red anticipated a lengthy fight, calling for, among other things, “a naval takeover of Halifax, to deny the port as a staging area for the British”; an “armored column” taking Montreal and Quebec; and a column from Buffalo “crippling the Canadian power grid.” Its end goal was for Canada to become part of “the United States of North America.”

In 1935, “the US Congress approved $57 million for an updated version of the plan,” and to build “three military airfields disguised as civilian airports on the Canadian border, which would be used to launch preemptive strikes against Canadian air forces and defenses.”

By this time, however, Britain had long since conceded that if the US did invade Canada, they would be unable to defend it, and also decided that losing Canada “would not be a fatal blow to Great Britain, whose empire then covered about 25% of the world’s landmass.”

War Plan Red was never put to use, was declassified in 1974, and signs of hostility between the two countries seem to have all but disappeared.

Or have they?

“During a Senate Appropriations Defense Subcommittee hearing on June 18, 2014,” writes Lippert, “Sen. Dan Coats (R-Ind.) said that, based on his knowledge, ‘the Pentagon has a contingency plan on the shelf for just about every possible scenario,’ including ‘an invasion by Canada.’ ”