What tactics did the US use to goad Mexico into provoking a war? And why did the US want to fight Mexico?

War for territory.

Explanation:

The United States is the first to resolve certain border disputes with Mexico through diplomacy. After the bureaucratic mission failed, the advance of the Mexican army in the northeast of the Rio Grande River was declared by the united states as an attack on the state's territorial integrity. It was an act that led to the war. The United States wanted the young American state's borders to be secure, and that is the main reason they went to war.