David Von Drehle: We get Cinco de Mayo wrong, but we’re not wrong to celebrate it

Some of history’s most significant what-ifs lie buried beneath layers of misunderstanding. So it is with Cinco de Mayo.

This annual celebration of Mexican culture gets bigger every year, fueled mainly by America’s love of a good party. Folks who aren’t from Mexico are often surprised to learn, as they quaff margaritas or savor tacos al carbon, that the holiday matters much less south of the border. Many mistakenly believe that May 5 is Mexican Independence Day, but that’s Sept. 16.

But it’s entirely appropriate that Cinco de Mayo matters more in the United States. The event commemorated on this holiday was a triumph of Mexican spirit and courage. For us, though, it just might have saved our nation.

When the future of the United States was threatened by the secession of 11 Southern states in 1860-61, Confederate strategists looked for help in two directions. One was Europe; the other was Mexico. Europe’s textile mills ran on Southern cotton. By cutting off the supply with an embargo, the rebels hoped to force France and Britain to recognize Southern independence. Mexico, meanwhile, was a potential ally – or maybe even a future member of the new Confederacy.

These two ideas came together in the early months of the Civil War, when a coalition of European powers sent an armed force to collect debts from the Mexican government. Abraham Lincoln’s diplomats scrambled for a way to pay the debts to keep Mexico happy and encourage the Europeans to leave. But Congress shortsightedly refused to provide the money.

As 1861 came to an end, only the French remained, camped on the Gulf Coast. French Emperor Napoleon III, nephew of the famous general, rued his uncle’s decision to sell French holdings in North America to Thomas Jefferson more than 50 years earlier. He decided to topple the Mexican government and reestablish Parisian power in the Americas.

So in the spring of 1862, the French began marching toward Mexico City, with the Confederate rebels cheering them on. After conquering Mexico, the French would be perfectly positioned to ally with the South and tip the balance of the Civil War.

The road from the port of Veracruz to Mexico City covered several hundred uphill miles. Roughly midway, a steep valley narrowed to a single passage below a towering volcanic peak. Here lay the city of Puebla, through which all traffic to the capital had to go.

A young Mexican general, Ignacio Zaragoza, placed a small, tough force at Puebla and scoured the countryside for volunteers to bolster the defense. A long trench was added to the city’s existing fortifications. Some 4,500 men occupied this position on May 5, when 6,000 French troops under Major General Charles de Lorencez came up the valley.

The overconfident French nobleman ordered an immediate attack. Zaragoza’s riflemen found easy targets as de Lorencez’s soldiers charged the trenches. Those Frenchmen who survived the climb met savage hand-to-hand fighting at the Mexican trenches.

A second charge also failed. As Union and Confederate generals would soon learn on battlefields from Corinth, Mississippi, to Gettysburg, a ferocious foe in an entrenched position had a tremendous advantage. The bloody field filled with French bodies.

When a third charge also failed, Zaragoza unleashed his cavalry on both flanks of the retreating French. The battle became a rout, and de Lorencez fell back all the way to Veracruz, where he counted his losses (as many as 500 killed and wounded) and waited to be reinforced from back home.

As it happened, the tide of the Civil War was just about to swing away from the North. In the summer of 1862, a Union campaign against the Confederate capital of Richmond fell to pieces and the rebels advanced on all fronts. Pressure for European intervention reached the boiling point.

Had a triumphant French army been raising the flag in Mexico City that summer, it might have made all the difference. The wavering Napoleon might have been emboldened to recognize the Confederacy, pulling the British along with him. Instead, the French army was licking its wounds, mangled by a smaller force of Mexican irregulars, and the emperor was momentarily chastened. Though France managed to topple the Mexican government the following year, its brief reign there came too late to help the South. The North had regained its momentum, and Lincoln was on his way to saving the Union.

Cinco de Mayo is a day to celebrate what-ifs that never transpired. What if Europe had taken the side of the South? What if the United States had shattered? What if there had been no superpower to defend democracy in the 20th century, only rival nations with incompatible goals vying for the real estate we call the United States? What if the men at Puebla had not saved America?

Put that in your margarita and sip it, amigos. ¡Viva Mexico! ¡Y viva los Estados Unidos!