Its not Mexican Independence Day today. This day commemorates instead a great Mexican victory over the invading French at the Battle of Puebla, May 5, 1862.

Now, U.S. Civil War buffs will notice that date. It was in the middle of Gen. George McClellans ill-fated Peninsula Campaign. Its when the young Napoleon was supposed to take the Confederate capital at Richmond but didnt.

McClellan had all of the famous French emperors qualities vanity, a lack of respect for elected officials, a love for pomp and show, and a lust for military glory except two: speed and decision. McClellan, President Lincoln complained, had the slows. And sending more troops to him was futile; they always got diverted. It was, in Lincolns phrase, like shoveling fleas.

France had a Napoleon then, too. The nephew of the famed conqueror had staged a military coup detat and installed himself as emperor. He titled himself Napoleon III. He was a thoroughly ridiculous figure who loved to pose in spectacular uniforms, who sported long, waxed mustachios, and who was determined to re-establish monarchy in the Western Hemisphere, in direct violation of Americas Monroe Doctrine.

Napoleon III tried to get the British to intervene in our Civil War on the side of the Confederacy. His whole purpose was to undercut the principle of republican government in the world.

President Lincoln was not wrong in seeing the Civil War as a peoples contest testing whether that government, or any government so conceived and so dedicated [could] long endure.

The Mexicans resisted Napoleon IIIs invasion. But it was hard for a people perennially suffering from bad government to put up an effective defense. Still, the victory at Puebla encouraged Mexicans to stand against a powerful European state. France had not been defeated since the Battle of Waterloo.

Napoleon III persuaded an Austrian Archduke, the hapless Maximilian, to become his puppet emperor in Mexico. The Northern press referred to Maximilian as the Archdupe. Maximilian was suitably dim-witted, but seems to have sincerely thought he was doing the Mexicans a favor.

Lincolns Secretary of State William Seward hoped to reunite America by declaring war on Britain and France. And throw in Spain, too, perhaps. Sewards fight 'em all plan was called wrap the world in flames.

President Lincoln politely sat on his friend Seward. One war at a time, Seward, Father Abraham said.

The Mexican victory against the French this day gave encouragement to all that republics could fight and win against monarchies. That was not so clear in the 1860s as it is today.

So we Americans who value our own independence can appreciate that Cinco de Mayo represents a victory over European interference in this hemisphere. It was as well a vindication of our own Monroe Doctrine.

Theres another reason to value Cinco de Mayo. Millions of loyal Americans are descended from legal immigrants from Mexico. Recognizing this holiday is a way of showing our appreciation of our fellow Americans of Mexican descent. And, as Canadas Stephen Harper just showed in a dramatic way, appealing to the essentially conservative, pro-family, pro-faith, and pro-life values of immigrants and the children of immigrants makes good politics, too. Viva Cinco de Mayo!