He could not be relieved from duty in the field where all his battles had been victories: the design would have been too transparent.

It was finally decided to send General Scott to Mexico in chief command, and to authorize him to carry out his own original plan: that is, capture Vera Cruz and march upon the capital of the country.
It was no doubt supposed that Scott's ambition would lead him to slaughter Taylor or destroy his chances for the Presidency, and yet it was hoped that he would not make sufficient capital himself to secure the prize.
The administration had indeed a most embarrassing problem to solve.

It was engaged in a war of conquest which must be carried to a successful issue, or the political object would be unattained.

Yet all the capable officers of the requisite rank belonged to the opposition, and the man selected for his lack of political ambition had himself become a prominent candidate for the Presidency.

It was necessary to destroy his chances promptly.