As the mustering out of the army proceeded, many changes in organization occurred. The most notable was that of July 25, 1866, when Grant was made a full General and Sherman was made Lieutenant-General. At the same time political feeling was running high at Washington. President Johnson had virtually left the Republican party, and was at loggerheads with the majority of Congress. Grant was looked to as the coming President, and accordingly many of Johnson's friends manifested much jealousy and hostility toward him. Sherman was in the west and so kept aloof from these controversies and intrigues, for which he had no love. But he maintained his old friendship with Grant, and inclined toward his side of every disputed question. While travelling on duty in New Mexico, in September, 1866, he was summoned to Washington, in haste. Going thither, he reported to Grant, who told him he did not know why the President had sent for him, unless in connection with Mexican affairs. Maximilian, supported by French troops, still held the imperial crown of that country, but was steadily being driven to the wall by the Republicans, who had elected Juarez President. The United States was about to send the Hon. Lewis Campbell thither as Minister, accredited to Juarez as the rightful head of the State, and President Johnson had ordered Grant to accompany him as an escort. Grant told Sherman that he would decline to obey this order as an illegal one, on the ground that the President had no right to send him out of the country on a diplomatic errand unaccompanied by troops; he believed it was a trick of Johnson's, to get rid of him. [Illustration: BATTLE OF EZRA CHURCH, JULY 28TH, 1864.] Then Sherman went to the President, who was very glad to see him. Said Johnson: "I am sending General Grant to Mexico, and I want you to command the army here in his absence." "But," said Sherman, "Grant will not go!" That startled Johnson, and he began arguing to show the need there was of Grant's going. Sherman repeated the positive statement that Grant would not go, and added that he did not think the President in that matter could afford to quarrel with the General. The upshot of the matter was, that Johnson decided to send Sherman instead of Grant, and Sherman consented to go, believing that thus he was preventing an open rupture between Grant and the Administration. Sherman and Campbell went to Mexico, and spent some weeks in trying to find Juarez, who was said to be with his army in the field. Not succeeding in their quest, they returned to New Orleans, and by Christmas Sherman was back at St. Louis, convinced that he had been sent as a ruse, on that idle errand. The President, he believed, simply wanted to send Grant somewhere to get him out of the way of his own political ambition.