It didn't begin with a memorable attack like Pearl Harbor; its cause, unlike slavery, isn't easily grasped; and it didn't end in a glorious victory like Cornwallis' surrender at Yorktown.

The War of 1812 is a murky, distant event to most Americans, but it produced moments that endure in the national memory.

The conflict came about gradually, unfolding over several years, all in the long shadow of Napoleon Bonaparte. The nearly constant warfare between the French emperor and Great Britain spurred tensions between Britain and the United States, which had been at peace since the American Revolution.

The British Navy needed massive manpower to fight Napoleon and resorted to stopping U.S. ships and seizing, or "impressing," British deserters, even those who were naturalized American citizens.

Mostly merchant ships were targeted, but in 1807, the HMS Leopard fired on and searched a Navy frigate, the USS Chesapeake, and seized four crewmen. Three more were killed and 18 were wounded. The humiliation sparked an outcry among Americans, many of whom called for war.

The Napoleonic wars also caused economic stresses, as Britain and France each tried to strangle the other's foreign trade. Embargoes and blockades cut off the United States from its largest trading partners and left its ships and cargoes vulnerable to seizure in violation of neutrality laws. In 1807, President Thomas Jefferson signed an embargo against U.S. trade with both countries. The result was an economic disaster for the United States, and the embargo was lifted after a little over a year.

There also was resentment of British support for Indian tribes, led by Tecumseh, that were fighting the westward expansion of the United States.

In 1812, Congress, pushed by young lawmakers known as the "War Hawks," cited all of these grievances in a vote to declare war on Britain. President James Madison signed it into law on June 18.

Neither country was ready for the conflict that followed. Britain's attention was focused squarely on Napoleon, and the United States had poor generals and divided politics.

The United States tried to invade Canada but was repulsed by British and Indian troops fighting defensively. But the United States scored a naval victory on Lake Erie thanks to Oliver Hazard Perry, whose brief but stirring account of the battle lived on after him: "We have met the enemy and they are ours."

The British blockaded U.S. ports and fought a series of memorable single-ship actions against the young U.S. Navy. In one of these, the USS Constitution earned its enduring nickname, "Old Ironsides," when British cannonballs bounced harmlessly off its hull.

In 1814, with Napoleon defeated, the British turned their full might on America and attacked on three fronts. In the north, they were defeated on Lake Champlain. In the east, they burned Washington, D.C., before being stopped at Baltimore in a battle that inspired the country's future national anthem. And in the south, they were defeated by Andrew Jackson at the Battle of New Orleans, remembered today in a popular folk song.

But Napoleon's downfall had erased most of the economic constraints that helped cause the war, and the impressment of sailors ceased. The two countries signed the Treaty of Ghent in late 1814, essentially ending the war in a draw.

J.RUDDY@THEDAY.COM