The issue dates at least to 1846, when President Polk deployed troops to the north bank of the Rio Grande River, provoking an attack by Mexico that started the Mexican War. Some contemporaries (including Abraham Lincoln, then a congressman) thought Polk violated the Constitution. But (contra Lincoln) the Constitution doesn’t say the President cannot act provocatively. Many things a President might do, in the conduct of diplomacy, for example, might provoke a war. A no-provocation rule would be impossible to implement and impose too great a restriction on presidential foreign policy.
This is not a correct account of Lincoln’s objection to the Mexican-American War. Lincoln never argued that the War was unnecessary and unconstitutional because the U.S. had acted provocatively in deploying forces along the border with Mexico. Rather, Lincoln contended that the U.S. had deployed its forces onto Mexican soil—had invaded Mexico—and thus had itself committed an act of war against Mexico. Lincoln’s view was that the War was unconstitutional because the U.S. was the unjustified aggressor, and Congress’s declaration of war was therefore grounded on a falsehood, namely, that first blood had been shed on U.S. soil.
In his definitive speech in the House of Representatives on Jan. 12, 1848, Lincoln said this:
The President, in his first war message of May 1846, declares that the soil was ours on which hostilities were commenced by Mexico; and he repeats that declaration, almost in the same language, in each successive annual message, thus showing that he esteems that point, a highly essential one. In the importance of that point, I entirely agree with the President. To my judgment, it is the very point, upon which he should be justified, or condemned. In his message of Decr. 1846, it seems to have occurred to him, as is certainly true, that title—ownership—to soil, or any thing else, is not a simple fact; but is a conclusion following one or more simple facts; and that it was incumbent upon him, to present the facts, from which he concluded, the soil was ours, on which the first blood of the war was shed.
An examination of the entire speech reveals that Lincoln never argued that Pres. Polk acted improperly or unconstitutionally because he deployed troops on U.S. soil in a manner that provoked a Mexican attack. Rather, he consistently argued that Polk acted improperly and unconstitutionally because he deployed troops onto Mexican soil, where first blood was shed.
Invading a neighboring country is, of course, very different from provoking that neighbor to invade one’s own country. What alarmed Lincoln was the former circumstance, not the latter.
Posted at 8:31 AM