to the Rio Grande and occupy a position commanding the encampment of the Mexican soldiers there.  The Mexican commander, thus threatened, attacked.  The Mexicans had thus begun the war.  Polk could thus allege his duty to prosecute it.  When the whole transaction was afterwards assailed his critics might be tempted to go, or represented as going, upon the false ground that only Congress can constitutionally declare war—­that is, of course, sanction purely offensive operations.  Long, however, before the dispute could come to a head, the brilliant successes of General Taylor and still more of General Scott, with a few trained troops against large undisciplined numbers, put all criticism at a disadvantage.  The City of Mexico was occupied by Scott in September, 1847, and peace, with the cession of the vast domain that had been coveted, was concluded in May, 1848.

War having begun, the line of the Whig opposition was to vote supplies and protest as best they might against the language endorsing Polk’s policy which, in the pettiest spirit of political manoeuvre, was sometimes incorporated in the votes.  In this Lincoln steadily supported them.  One of his only two speeches of any length in Congress was made on the occasion of a vote of this kind in 1848.  The subject was by that time so stale that his speech could hardly make much impression, but it appears to-day an extraordinarily clear, strong, upright presentment of the complex and unpopular case against the war.  His other long speech is elevated above buffoonery by a brief, cogent, and earnest passage on the same theme, but it was a frank piece of clowning on a licensed occasion.  It was the fashion for the House when its own dissolution and a Presidential election were both imminent to have a sort of rhetorical scrimmage in which members on both sides spoke for the edification of their own constituencies and that of Buncombe.  The Whigs were now happy in having “diverted the war-thunder against the Democrats” by running for the Presidency General Taylor, a good soldier who did not know whether he was a Whig or a Democrat, but who, besides being a hero of the war, was inoffensive to the South, for he lived in Louisiana and had slaves of his own.  It is characteristic of the time that the Democrats, in whose counsels the Southern men prevailed, now began a practice of choosing Northern candidates, and nominated General Cass of Michigan, whose distinction had not been won in war.  The Democratic Congressmen in this debate made game of the Whigs, with their war-hero, and seem to have carried a crude manner of pleasantry pretty far when Lincoln determined to show them that they could be beaten at that game.  He seems to have succeeded admirably, with a burlesque comparison, too long to quote, of General Cass’s martial exploits with his own, and other such-like matter enhanced by the most extravagant Western manner and delivery.