Not the greatest war picture I've ever seen. The characters are stock, and the only one with any warmth or depth is Billy Bob Thornton as Davy Crockett.

But it did get me interested in that brief period of time when the North American continent housed three republics. So I went back to Thomas Bailey's Diplomatic History of the American People for a little refresher. It turns out that the Mexican War, which Lincoln opposed during his sole term in the U.S. House, started out popular enough, but the public went sour on it pretty fast. The Whigs, opposition to President Polk's Democrats, both took advantage of and led the opposition to the war. Polk found himself in a political bind:

The growth of opposition to the war was particularly ominous. As early as May 1846, the Boston Atlas had declared, "It would be a sad and woeful joy, but a joy nevertheless, to hear that the hordes under [Winfield] Scott and [Zachary] Taylor were, every man of them, swept into the next world."

1846's version of "a million Mogadishus."

Following the elections of 1846, the Whigs had enjoyed a majority in the House of Representatives, and in January 1848, that body resolved, 85 to 81, that the war had been "unnecessarily and unconstitutionally begun by the President of the United States." The danger loomed that the Whig House might block further appropriations for the armies in the field.

Bailey is leftish but not leftist, and there's no reason to think he's making things up. This was a war seen as voluntary, although as part of a larger struggle for the shape of North America. Polk wanted Callifornia, but earlier missions to try to buy the place hadn't even been received by the Mexicans. Texas wanted to join the union, but anti-slavery forces saw a plot. It had tried several times to be annexed, but had failed. Mexico had never recognized the country's independence. The US may well have invited war with Mexico by annexing Texas and then backing its maximalist territorial claims. But it's no exaggeration to say that another independent republic could have threatened the future position of the US as the dominant power on the continent.

And yet, with all that at stake, the government basically failed to make its case, and invited the kind of talk that we associate with MoveOn and A.N.S.W.E.R.

The Republic has survived this kind of talk before, and it will survive it again. These people must be engaged in debate; they certainly can't have the field to themselves. But if the cause it just, and it is, and if the reasons are clear, and they must be made so, then we have nothing to worry about.