what was desired of him, saying that, if the Rio Grande boundary was really the ultimatum of the United States, a prompt advance was indeed advisable; but in that case, as Mexico had neither declared war nor committed any overt act of hostility, he wanted definite authority from the War Department for a forward movement. This seems to have been an unwelcome request. Definite orders did not come for months. Meanwhile operations on another line were going on.
In September Buchanan had inquired of the Mexican government, through the American Consul, whether it would “receive an envoy from the United States intrusted with full powers to adjust all questions in dispute between the two governments.” The Mexican government promptly declared itself ready to receive a “commissioner” with full power to settle “the present dispute,” meaning the dispute about Texas. Polk then appointed Slidell of Louisiana, as “Envoy Extraordinary and Minister Plenipotentiary” to enter into negotiations about a variety of matters. It was not only Texas the administration had in mind, but also the Mexican province, California. While this was going on, Commodore Sloat, commanding the Pacific squadron of the American navy, was under instructions, as soon as he should ascertain with certainty that Mexico had declared war against the United States, at once to possess himself of the port of San Francisco, and to blockade or occupy such other ports as his force would permit;
